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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.14351">arXiv:2405.14351</a> <span> [<a href="https://arxiv.org/pdf/2405.14351">pdf</a>, <a href="https://arxiv.org/format/2405.14351">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/pasa.2024.96">10.1017/pasa.2024.96 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The ORT and the uGMRT Pulsar Monitoring Program : Pulsar Timing Irregularities & the Gaussian Process Realization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Grover%2C+H">Himanshu Grover</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=G%C3%BCgercino%C4%9Flu%2C+E">Erbil G眉gercino臒lu</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">Paramasivan Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Bandyopadhyay%2C+D">Debades Bandyopadhyay</a>, <a href="/search/astro-ph?searchtype=author&query=Chibueze%2C+J+O">James O. Chibueze</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Eya%2C+I+O">Innocent O. Eya</a>, <a href="/search/astro-ph?searchtype=author&query=Kundu%2C+A">Anu Kundu</a>, <a href="/search/astro-ph?searchtype=author&query=Urama%2C+J+O">Johnson O. Urama</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.14351v2-abstract-short" style="display: inline;"> The spin-down law of pulsars is generally perturbed by two types of timing irregularities: glitches and timing noise. Glitches are sudden changes in the rotational frequency of pulsars, while timing noise is a discernible stochastic wandering in the phase, period, or spin-down rate of a pulsar. We present the timing results of a sample of glitching pulsars observed using the Ooty Radio Telescope (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.14351v2-abstract-full').style.display = 'inline'; document.getElementById('2405.14351v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.14351v2-abstract-full" style="display: none;"> The spin-down law of pulsars is generally perturbed by two types of timing irregularities: glitches and timing noise. Glitches are sudden changes in the rotational frequency of pulsars, while timing noise is a discernible stochastic wandering in the phase, period, or spin-down rate of a pulsar. We present the timing results of a sample of glitching pulsars observed using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT). Our findings include timing noise analysis for 17 pulsars, with seven being reported for the first time. We detected five glitches in four pulsars and a glitch-like event in PSR J1825-0935. The frequency evolution of glitch in pulsars, J0742-2822 and J1740-3015, is presented for the first time. Additionally, we report timing noise results for three glitching pulsars. The timing noise was analyzed separately in the pre-glitch region and post-glitch regions. We observed an increase in the red noise parameters in the post-glitch regions, where exponential recovery was considered in the noise analysis. Timing noise can introduce ambiguities in the correct evaluation of glitch observations. Hence, it is important to consider timing noise in glitch analysis. We propose an innovative glitch verification approach designed to discern between a glitch and strong timing noise. The novel glitch analysis technique is also demonstrated using the observed data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.14351v2-abstract-full').style.display = 'none'; document.getElementById('2405.14351v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 23 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 12 figures. Accepted for publication in PASA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.01875">arXiv:2312.01875</a> <span> [<a href="https://arxiv.org/pdf/2312.01875">pdf</a>, <a href="https://arxiv.org/format/2312.01875">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/pasa.2024.30">10.1017/pasa.2024.30 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Low-frequency pulse-jitter measurement with the uGMRT I : PSR J0437$-$4715 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T. Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Takahashi%2C+K">Keitaro Takahashi</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">Swetha Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">Debabrata Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">Churchil Dwivedi</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Jacob%2C+S+J">Shebin Jose Jacob</a>, <a href="/search/astro-ph?searchtype=author&query=Kareem%2C+F">Fazal Kareem</a>, <a href="/search/astro-ph?searchtype=author&query=K%2C+N">Nobleson K</a>, <a href="/search/astro-ph?searchtype=author&query=Mamidipaka%2C+P">Pragna Mamidipaka</a>, <a href="/search/astro-ph?searchtype=author&query=Paladi%2C+A+K">Avinash Kumar Paladi</a>, <a href="/search/astro-ph?searchtype=author&query=B%2C+A+P">Arul Pandian B</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+P">Prerna Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Srivastava%2C+A">Aman Srivastava</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M">Mayuresh Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.01875v3-abstract-short" style="display: inline;"> High-precision pulsar timing observations are limited in their accuracy by the jitter noise that appears in the arrival time of pulses. Therefore, it is important to systematically characterise the amplitude of the jitter noise and its variation with frequency. In this paper, we provide jitter measurements from low-frequency wideband observations of PSR J0437$-$4715 using data obtained as part of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01875v3-abstract-full').style.display = 'inline'; document.getElementById('2312.01875v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.01875v3-abstract-full" style="display: none;"> High-precision pulsar timing observations are limited in their accuracy by the jitter noise that appears in the arrival time of pulses. Therefore, it is important to systematically characterise the amplitude of the jitter noise and its variation with frequency. In this paper, we provide jitter measurements from low-frequency wideband observations of PSR J0437$-$4715 using data obtained as part of the Indian Pulsar Timing Array experiment. We were able to detect jitter in both the 300 - 500 MHz and 1260 - 1460 MHz observations of the upgraded Giant Metrewave Radio Telescope (uGMRT). The former is the first jitter measurement for this pulsar below 700 MHz, and the latter is in good agreement with results from previous studies. In addition, at 300 - 500 MHz, we investigated the frequency dependence of the jitter by calculating the jitter for each sub-banded arrival time of pulses. We found that the jitter amplitude increases with frequency. This trend is opposite as compared to previous studies, indicating that there is a turnover at intermediate frequencies. It will be possible to investigate this in more detail with uGMRT observations at 550 - 750 MHz and future high sensitive wideband observations from next generation telescopes, such as the Square Kilometre Array. We also explored the effect of jitter on the high precision dispersion measure (DM) measurements derived from short duration observations. We find that even though the DM precision will be better at lower frequencies due to the smaller amplitude of jitter noise, it will limit the DM precision for high signal-to-noise observations, which are of short durations. This limitation can be overcome by integrating for a long enough duration optimised for a given pulsar. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01875v3-abstract-full').style.display = 'none'; document.getElementById('2312.01875v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 12 figures, 3 tables, accepted for Publication of the Astronomical Society of Australia</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.16765">arXiv:2309.16765</a> <span> [<a href="https://arxiv.org/pdf/2309.16765">pdf</a>, <a href="https://arxiv.org/format/2309.16765">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stae2405">10.1093/mnras/stae2405 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Improving DM estimates using low-frequency scattering-broadening estimates </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Kareem%2C+F">Fazal Kareem</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">Churchil Dwivedi</a>, <a href="/search/astro-ph?searchtype=author&query=Jacob%2C+S+J">Shebin Jose Jacob</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">Swetha Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">Debabrata Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Debnath%2C+J">Jyotijwal Debnath</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Kato%2C+R">Ryo Kato</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Marmat%2C+P">Piyush Marmat</a>, <a href="/search/astro-ph?searchtype=author&query=Nobleson%2C+K">K. Nobleson</a>, <a href="/search/astro-ph?searchtype=author&query=Paladi%2C+A+K">Avinash K. Paladi</a>, <a href="/search/astro-ph?searchtype=author&query=B.%2C+A+P">Arul Pandian B.</a> , et al. (6 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.16765v2-abstract-short" style="display: inline;"> A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces slowly varying time delays in the measured times-of-arrival similar to those introduced by passing gravitational waves. In this article, we present an improved m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.16765v2-abstract-full').style.display = 'inline'; document.getElementById('2309.16765v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.16765v2-abstract-full" style="display: none;"> A pulsar's pulse profile gets broadened at low frequencies due to dispersion along the line of sight or due to multi-path propagation. The dynamic nature of the interstellar medium makes both of these effects time-dependent and introduces slowly varying time delays in the measured times-of-arrival similar to those introduced by passing gravitational waves. In this article, we present an improved method to correct for such delays by obtaining unbiased dispersion measure (DM) measurements by using low-frequency estimates of the scattering parameters. We evaluate this method by comparing the obtained DM estimates with those, where scatter-broadening is ignored using simulated data. A bias is seen in the estimated DMs for simulated data with pulse-broadening with a larger variability for a data set with a variable frequency scaling index, $伪$, as compared to that assuming a Kolmogorov turbulence. Application of the proposed method removes this bias robustly for data with band averaged signal-to-noise ratio larger than 100. We report the measurements of the scatter-broadening time and $伪$ from analysis of PSR J1643$-$1224, observed with upgraded Giant Metrewave Radio Telescope as part of the Indian Pulsar Timing Array experiment. These scattering parameters were found to vary with epoch and $伪$ was different from that expected for Kolmogorov turbulence. Finally, we present the DM time-series after application of this technique to PSR J1643$-$1224. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.16765v2-abstract-full').style.display = 'none'; document.getElementById('2309.16765v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 8 figures, Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.00693">arXiv:2309.00693</a> <span> [<a href="https://arxiv.org/pdf/2309.00693">pdf</a>, <a href="https://arxiv.org/format/2309.00693">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> Comparing recent PTA results on the nanohertz stochastic gravitational wave background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+International+Pulsar+Timing+Array+Collaboration"> The International Pulsar Timing Array Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Agazie%2C+G">G. Agazie</a>, <a href="/search/astro-ph?searchtype=author&query=Antoniadis%2C+J">J. Antoniadis</a>, <a href="/search/astro-ph?searchtype=author&query=Anumarlapudi%2C+A">A. Anumarlapudi</a>, <a href="/search/astro-ph?searchtype=author&query=Archibald%2C+A+M">A. M. Archibald</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">S. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arzoumanian%2C+Z">Z. Arzoumanian</a>, <a href="/search/astro-ph?searchtype=author&query=Askew%2C+J">J. Askew</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">M. Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Bailes%2C+M">M. Bailes</a>, <a href="/search/astro-ph?searchtype=author&query=Nielsen%2C+A+-+B">A. -S. Bak Nielsen</a>, <a href="/search/astro-ph?searchtype=author&query=Baker%2C+P+T">P. T. Baker</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">A. Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=B%C3%A9csy%2C+B">B. B茅csy</a>, <a href="/search/astro-ph?searchtype=author&query=Berthereau%2C+A">A. Berthereau</a>, <a href="/search/astro-ph?searchtype=author&query=Bhat%2C+N+D+R">N. D. R. Bhat</a>, <a href="/search/astro-ph?searchtype=author&query=Blecha%2C+L">L. Blecha</a>, <a href="/search/astro-ph?searchtype=author&query=Bonetti%2C+M">M. Bonetti</a>, <a href="/search/astro-ph?searchtype=author&query=Bortolas%2C+E">E. Bortolas</a>, <a href="/search/astro-ph?searchtype=author&query=Brazier%2C+A">A. Brazier</a>, <a href="/search/astro-ph?searchtype=author&query=Brook%2C+P+R">P. R. Brook</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a> , et al. (220 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.00693v1-abstract-short" style="display: inline;"> The Australian, Chinese, European, Indian, and North American pulsar timing array (PTA) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational wave background (GWB). Given that each PTA made different choices in modeling their data, we perform a comparison of the GWB and individual pulsar noise parameters across the results reported from the PTA… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.00693v1-abstract-full').style.display = 'inline'; document.getElementById('2309.00693v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.00693v1-abstract-full" style="display: none;"> The Australian, Chinese, European, Indian, and North American pulsar timing array (PTA) collaborations recently reported, at varying levels, evidence for the presence of a nanohertz gravitational wave background (GWB). Given that each PTA made different choices in modeling their data, we perform a comparison of the GWB and individual pulsar noise parameters across the results reported from the PTAs that constitute the International Pulsar Timing Array (IPTA). We show that despite making different modeling choices, there is no significant difference in the GWB parameters that are measured by the different PTAs, agreeing within $1蟽$. The pulsar noise parameters are also consistent between different PTAs for the majority of the pulsars included in these analyses. We bridge the differences in modeling choices by adopting a standardized noise model for all pulsars and PTAs, finding that under this model there is a reduction in the tension in the pulsar noise parameters. As part of this reanalysis, we "extended" each PTA's data set by adding extra pulsars that were not timed by that PTA. Under these extensions, we find better constraints on the GWB amplitude and a higher signal-to-noise ratio for the Hellings and Downs correlations. These extensions serve as a prelude to the benefits offered by a full combination of data across all pulsars in the IPTA, i.e., the IPTA's Data Release 3, which will involve not just adding in additional pulsars, but also including data from all three PTAs where any given pulsar is timed by more than as single PTA. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.00693v1-abstract-full').style.display = 'none'; document.getElementById('2309.00693v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 9 figures, submitted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.16227">arXiv:2306.16227</a> <span> [<a href="https://arxiv.org/pdf/2306.16227">pdf</a>, <a href="https://arxiv.org/format/2306.16227">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> </div> <p class="title is-5 mathjax"> The second data release from the European Pulsar Timing Array: IV. Implications for massive black holes, dark matter and the early Universe </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antoniadis%2C+J">J. Antoniadis</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">S. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Auclair%2C+P">P. Auclair</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">M. Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Nielsen%2C+A+-+B">A. -S. Bak Nielsen</a>, <a href="/search/astro-ph?searchtype=author&query=Barausse%2C+E">E. Barausse</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">A. Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Berthereau%2C+A">A. Berthereau</a>, <a href="/search/astro-ph?searchtype=author&query=Bonetti%2C+M">M. Bonetti</a>, <a href="/search/astro-ph?searchtype=author&query=Bortolas%2C+E">E. Bortolas</a>, <a href="/search/astro-ph?searchtype=author&query=Brook%2C+P+R">P. R. Brook</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. N. Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Caprini%2C+C">C. Caprini</a>, <a href="/search/astro-ph?searchtype=author&query=Chalumeau%2C+A">A. Chalumeau</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Chanlaridis%2C+S">S. Chanlaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Crisostomi%2C+M">M. Crisostomi</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">S. Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">D. Deb</a> , et al. (89 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.16227v2-abstract-short" style="display: inline;"> The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases respectively, with the correlation properties of a gravitational wave background (GWB). Such signal may have its origin in a number of physical processes including a cosmic population of inspiralling sup… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16227v2-abstract-full').style.display = 'inline'; document.getElementById('2306.16227v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.16227v2-abstract-full" style="display: none;"> The European Pulsar Timing Array (EPTA) and Indian Pulsar Timing Array (InPTA) collaborations have measured a low-frequency common signal in the combination of their second and first data releases respectively, with the correlation properties of a gravitational wave background (GWB). Such signal may have its origin in a number of physical processes including a cosmic population of inspiralling supermassive black hole binaries (SMBHBs); inflation, phase transitions, cosmic strings and tensor mode generation by non-linear evolution of scalar perturbations in the early Universe; oscillations of the Galactic potential in the presence of ultra-light dark matter (ULDM). At the current stage of emerging evidence, it is impossible to discriminate among the different origins. Therefore, in this paper, we consider each process separately, and investigate the implications of the signal under the hypothesis that it is generated by that specific process. We find that the signal is consistent with a cosmic population of inspiralling SMBHBs, and its relatively high amplitude can be used to place constraints on binary merger timescales and the SMBH-host galaxy scaling relations. If this origin is confirmed, this is the first direct evidence that SMBHBs merge in nature, adding an important observational piece to the puzzle of structure formation and galaxy evolution. As for early Universe processes, the measurement would place tight constraints on the cosmic string tension and on the level of turbulence developed by first-order phase transitions. Other processes would require non-standard scenarios, such as a blue-tilted inflationary spectrum or an excess in the primordial spectrum of scalar perturbations at large wavenumbers. Finally, a ULDM origin of the detected signal is disfavoured, which leads to direct constraints on the abundance of ULDM in our Galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16227v2-abstract-full').style.display = 'none'; document.getElementById('2306.16227v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">30 pages, 23 figures, replaced to match the version published in Astronomy & Astrophysics, note the change in the numbering order in the series (now paper IV)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.16226">arXiv:2306.16226</a> <span> [<a href="https://arxiv.org/pdf/2306.16226">pdf</a>, <a href="https://arxiv.org/format/2306.16226">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202348568">10.1051/0004-6361/202348568 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The second data release from the European Pulsar Timing Array V. Search for continuous gravitational wave signals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antoniadis%2C+J">J. Antoniadis</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">S. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">M. Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Nielsen%2C+A+S+B">A. S. Bak Nielsen</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">A. Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Berthereau%2C+A">A. Berthereau</a>, <a href="/search/astro-ph?searchtype=author&query=Bonetti%2C+M">M. Bonetti</a>, <a href="/search/astro-ph?searchtype=author&query=Bortolas%2C+E">E. Bortolas</a>, <a href="/search/astro-ph?searchtype=author&query=Brook%2C+P+R">P. R. Brook</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. N. Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Chalumeau%2C+A">A. Chalumeau</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Chanlaridis%2C+S">S. Chanlaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">S. Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">D. Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">S. Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Dhanda-Batra%2C+N">N. Dhanda-Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">C. Dwivedi</a> , et al. (75 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.16226v3-abstract-short" style="display: inline;"> We present the results of a search for continuous gravitational wave signals (CGWs) in the second data release (DR2) of the European Pulsar Timing Array (EPTA) collaboration. The most significant candidate event from this search has a gravitational wave frequency of 4-5 nHz. Such a signal could be generated by a supermassive black hole binary (SMBHB) in the local Universe. We present the results o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16226v3-abstract-full').style.display = 'inline'; document.getElementById('2306.16226v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.16226v3-abstract-full" style="display: none;"> We present the results of a search for continuous gravitational wave signals (CGWs) in the second data release (DR2) of the European Pulsar Timing Array (EPTA) collaboration. The most significant candidate event from this search has a gravitational wave frequency of 4-5 nHz. Such a signal could be generated by a supermassive black hole binary (SMBHB) in the local Universe. We present the results of a follow-up analysis of this candidate using both Bayesian and frequentist methods. The Bayesian analysis gives a Bayes factor of 4 in favor of the presence of the CGW over a common uncorrelated noise process, while the frequentist analysis estimates the p-value of the candidate to be 1%, also assuming the presence of common uncorrelated red noise. However, comparing a model that includes both a CGW and a gravitational wave background (GWB) to a GWB only, the Bayes factor in favour of the CGW model is only 0.7. Therefore, we cannot conclusively determine the origin of the observed feature, but we cannot rule it out as a CGW source. We present results of simulations that demonstrate that data containing a weak gravitational wave background can be misinterpreted as data including a CGW and vice versa, providing two plausible explanations of the EPTA DR2 data. Further investigations combining data from all PTA collaborations will be needed to reveal the true origin of this feature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16226v3-abstract-full').style.display = 'none'; document.getElementById('2306.16226v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 figures, 15 pages, accepted</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 690, A118 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.16225">arXiv:2306.16225</a> <span> [<a href="https://arxiv.org/pdf/2306.16225">pdf</a>, <a href="https://arxiv.org/format/2306.16225">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346842">10.1051/0004-6361/202346842 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The second data release from the European Pulsar Timing Array II. Customised pulsar noise models for spatially correlated gravitational waves </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antoniadis%2C+J">J. Antoniadis</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">S. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">M. Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Nielsen%2C+A+S+B">A. S. Bak Nielsen</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">A. Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Berthereau%2C+A">A. Berthereau</a>, <a href="/search/astro-ph?searchtype=author&query=Bonetti%2C+M">M. Bonetti</a>, <a href="/search/astro-ph?searchtype=author&query=Bortolas%2C+E">E. Bortolas</a>, <a href="/search/astro-ph?searchtype=author&query=Brook%2C+P+R">P. R. Brook</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. N. Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Chalumeau%2C+A">A. Chalumeau</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Chanlaridis%2C+S">S. Chanlaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">S. Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">D. Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">S. Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Dhanda-Batra%2C+N">N. Dhanda-Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">C. Dwivedi</a> , et al. (73 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.16225v1-abstract-short" style="display: inline;"> The nanohertz gravitational wave background (GWB) is expected to be an aggregate signal of an ensemble of gravitational waves emitted predominantly by a large population of coalescing supermassive black hole binaries in the centres of merging galaxies. Pulsar timing arrays, ensembles of extremely stable pulsars, are the most precise experiments capable of detecting this background. However, the su… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16225v1-abstract-full').style.display = 'inline'; document.getElementById('2306.16225v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.16225v1-abstract-full" style="display: none;"> The nanohertz gravitational wave background (GWB) is expected to be an aggregate signal of an ensemble of gravitational waves emitted predominantly by a large population of coalescing supermassive black hole binaries in the centres of merging galaxies. Pulsar timing arrays, ensembles of extremely stable pulsars, are the most precise experiments capable of detecting this background. However, the subtle imprints that the GWB induces on pulsar timing data are obscured by many sources of noise. These must be carefully characterized to increase the sensitivity to the GWB. In this paper, we present a novel technique to estimate the optimal number of frequency coefficients for modelling achromatic and chromatic noise and perform model selection. We also incorporate a new model to fit for scattering variations in the pulsar timing package temponest and created realistic simulations of the European Pulsar Timing Array (EPTA) datasets that allowed us to test the efficacy of our noise modelling algorithms. We present an in-depth analysis of the noise properties of 25 millisecond pulsars (MSPs) that form the second data release (DR2) of the EPTA and investigate the effect of incorporating low-frequency data from the Indian PTA collaboration. We use enterprise and temponest packages to compare noise models with those reported with the EPTA DR1. We find that, while in some pulsars we can successfully disentangle chromatic from achromatic noise owing to the wider frequency coverage in DR2, in others the noise models evolve in a more complicated way. We also find evidence of long-term scattering variations in PSR J1600$-$3053. Through our simulations, we identify intrinsic biases in our current noise analysis techniques and discuss their effect on GWB searches. The results presented here directly help improve sensitivity to the GWB and are already being used as part of global PTA efforts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16225v1-abstract-full').style.display = 'none'; document.getElementById('2306.16225v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 6 figures, 9 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 678, A49 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.16214">arXiv:2306.16214</a> <span> [<a href="https://arxiv.org/pdf/2306.16214">pdf</a>, <a href="https://arxiv.org/format/2306.16214">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346844">10.1051/0004-6361/202346844 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The second data release from the European Pulsar Timing Array III. Search for gravitational wave signals </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antoniadis%2C+J">J. Antoniadis</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">S. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">M. Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Nielsen%2C+A+-+B">A. -S. Bak Nielsen</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">A. Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Berthereau%2C+A">A. Berthereau</a>, <a href="/search/astro-ph?searchtype=author&query=Bonetti%2C+M">M. Bonetti</a>, <a href="/search/astro-ph?searchtype=author&query=Bortolas%2C+E">E. Bortolas</a>, <a href="/search/astro-ph?searchtype=author&query=Brook%2C+P+R">P. R. Brook</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. N. Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Chalumeau%2C+A">A. Chalumeau</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Chanlaridis%2C+S">S. Chanlaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">S. Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">D. Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">S. Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Dhanda-Batra%2C+N">N. Dhanda-Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">C. Dwivedi</a> , et al. (73 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.16214v1-abstract-short" style="display: inline;"> We present the results of the search for an isotropic stochastic gravitational wave background (GWB) at nanohertz frequencies using the second data release of the European Pulsar Timing Array (EPTA) for 25 millisecond pulsars and a combination with the first data release of the Indian Pulsar Timing Array (InPTA). We analysed (i) the full 24.7-year EPTA data set, (ii) its 10.3-year subset based on… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16214v1-abstract-full').style.display = 'inline'; document.getElementById('2306.16214v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.16214v1-abstract-full" style="display: none;"> We present the results of the search for an isotropic stochastic gravitational wave background (GWB) at nanohertz frequencies using the second data release of the European Pulsar Timing Array (EPTA) for 25 millisecond pulsars and a combination with the first data release of the Indian Pulsar Timing Array (InPTA). We analysed (i) the full 24.7-year EPTA data set, (ii) its 10.3-year subset based on modern observing systems, (iii) the combination of the full data set with the first data release of the InPTA for ten commonly timed millisecond pulsars, and (iv) the combination of the 10.3-year subset with the InPTA data. These combinations allowed us to probe the contributions of instrumental noise and interstellar propagation effects. With the full data set, we find marginal evidence for a GWB, with a Bayes factor of four and a false alarm probability of $4\%$. With the 10.3-year subset, we report evidence for a GWB, with a Bayes factor of $60$ and a false alarm probability of about $0.1\%$ ($\gtrsim 3蟽$ significance). The addition of the InPTA data yields results that are broadly consistent with the EPTA-only data sets, with the benefit of better noise modelling. Analyses were performed with different data processing pipelines to test the consistency of the results from independent software packages. The inferred spectrum from the latest EPTA data from new generation observing systems is rather uncertain and in mild tension with the common signal measured in the full data set. However, if the spectral index is fixed at 13/3, the two data sets give a similar amplitude of ($2.5\pm0.7)\times10^{-15}$ at a reference frequency of $1\,{\rm yr}^{-1}$. By continuing our detection efforts as part of the International Pulsar Timing Array (IPTA), we expect to be able to improve the measurement of spatial correlations and better characterise this signal in the coming years. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.16214v1-abstract-full').style.display = 'none'; document.getElementById('2306.16214v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">21 pages, 14 figures, 4 appendix figures, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 678, A50 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.13072">arXiv:2304.13072</a> <span> [<a href="https://arxiv.org/pdf/2304.13072">pdf</a>, <a href="https://arxiv.org/format/2304.13072">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stad3122">10.1093/mnras/stad3122 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-band Extension of the Wideband Timing Technique </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Paladi%2C+A+K">Avinash Kumar Paladi</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">Churchil Dwivedi</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+P">Prerna Rana</a>, <a href="/search/astro-ph?searchtype=author&query=K%2C+N">Nobleson K</a>, <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=Deb%2C+D">Debabrata Deb</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">Swetha Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M A Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Debnath%2C+J">Jyotijwal Debnath</a>, <a href="/search/astro-ph?searchtype=author&query=Kareem%2C+F">Fazal Kareem</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">Paramasivan Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.13072v2-abstract-short" style="display: inline;"> The wideband timing technique enables the high-precision simultaneous estimation of pulsar Times of Arrival (ToAs) and Dispersion Measures (DMs) while effectively modeling frequency-dependent profile evolution. We present two novel independent methods that extend the standard wideband technique to handle simultaneous multi-band pulsar data incorporating profile evolution over a larger frequency sp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13072v2-abstract-full').style.display = 'inline'; document.getElementById('2304.13072v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.13072v2-abstract-full" style="display: none;"> The wideband timing technique enables the high-precision simultaneous estimation of pulsar Times of Arrival (ToAs) and Dispersion Measures (DMs) while effectively modeling frequency-dependent profile evolution. We present two novel independent methods that extend the standard wideband technique to handle simultaneous multi-band pulsar data incorporating profile evolution over a larger frequency span to estimate DMs and ToAs with enhanced precision. We implement the wideband likelihood using the libstempo python interface to perform wideband timing in the tempo2 framework. We present the application of these techniques to the dataset of fourteen millisecond pulsars observed simultaneously in Band 3 (300 - 500 MHz) and Band 5 (1260 - 1460 MHz) of the upgraded Giant Metrewave Radio Telescope (uGMRT) with a large band gap of 760 MHz as a part of the Indian Pulsar Timing Array (InPTA) campaign. We achieve increased ToA and DM precision and sub-microsecond root mean square post-fit timing residuals by combining simultaneous multi-band pulsar observations done in non-contiguous bands for the first time using our novel techniques. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13072v2-abstract-full').style.display = 'none'; document.getElementById('2304.13072v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.12105">arXiv:2303.12105</a> <span> [<a href="https://arxiv.org/pdf/2303.12105">pdf</a>, <a href="https://arxiv.org/format/2303.12105">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1103/PhysRevD.108.023008">10.1103/PhysRevD.108.023008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Noise analysis of the Indian Pulsar Timing Array data release I </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Srivastava%2C+A">Aman Srivastava</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M">Mayuresh Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Chalumeau%2C+A">Aur茅lien Chalumeau</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=K.%2C+N">Nobleson K.</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+S">Swetha Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Dwivedi%2C+C">Churchil Dwivedi</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A. Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">Kuo Liu</a> , et al. (6 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.12105v2-abstract-short" style="display: inline;"> The Indian Pulsar Timing Array (InPTA) collaboration has recently made its first official data release (DR1) for a sample of 14 pulsars using 3.5 years of uGMRT observations. We present the results of single-pulsar noise analysis for each of these 14 pulsars using the InPTA DR1. For this purpose, we consider white noise, achromatic red noise, dispersion measure (DM) variations, and scattering vari… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12105v2-abstract-full').style.display = 'inline'; document.getElementById('2303.12105v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.12105v2-abstract-full" style="display: none;"> The Indian Pulsar Timing Array (InPTA) collaboration has recently made its first official data release (DR1) for a sample of 14 pulsars using 3.5 years of uGMRT observations. We present the results of single-pulsar noise analysis for each of these 14 pulsars using the InPTA DR1. For this purpose, we consider white noise, achromatic red noise, dispersion measure (DM) variations, and scattering variations in our analysis. We apply Bayesian model selection to obtain the preferred noise models among these for each pulsar. For PSR J1600$-$3053, we find no evidence of DM and scattering variations, while for PSR J1909$-$3744, we find no significant scattering variations. Properties vary dramatically among pulsars. For example, we find a strong chromatic noise with chromatic index $\sim$ 2.9 for PSR J1939+2134, indicating the possibility of a scattering index that doesn't agree with that expected for a Kolmogorov scattering medium consistent with similar results for millisecond pulsars in past studies. Despite the relatively short time baseline, the noise models broadly agree with the other PTAs and provide, at the same time, well-constrained DM and scattering variations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12105v2-abstract-full').style.display = 'none'; document.getElementById('2303.12105v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in PRD, 30 pages, 17 figures, 4 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.05306">arXiv:2301.05306</a> <span> [<a href="https://arxiv.org/pdf/2301.05306">pdf</a>, <a href="https://arxiv.org/format/2301.05306">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad06bb">10.3847/1538-4357/ad06bb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Simultaneous Dual-Frequency Scintillation Arc Survey of Six Bright Canonical Pulsars Using the Upgraded Giant Metrewave Radio Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Turner%2C+J+E">Jacob E. Turner</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=McLaughlin%2C+M+A">Maura A. McLaughlin</a>, <a href="/search/astro-ph?searchtype=author&query=Stinebring%2C+D+R">Daniel R. Stinebring</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.05306v4-abstract-short" style="display: inline;"> We use the upgraded Giant Metrewave Radio Telescope to measure scintillation arc properties in six bright canonical pulsars with simultaneous dual frequency coverage. These observations at frequencies from 300 to 750 MHz allowed for detailed analysis of arc evolution across frequency and epoch. We perform more robust determinations of frequency dependence for arc curvature, scintillation bandwidth… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05306v4-abstract-full').style.display = 'inline'; document.getElementById('2301.05306v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.05306v4-abstract-full" style="display: none;"> We use the upgraded Giant Metrewave Radio Telescope to measure scintillation arc properties in six bright canonical pulsars with simultaneous dual frequency coverage. These observations at frequencies from 300 to 750 MHz allowed for detailed analysis of arc evolution across frequency and epoch. We perform more robust determinations of frequency dependence for arc curvature, scintillation bandwidth, and scintillation timescale, and comparison between arc curvature and pseudo-curvature than allowed by single-frequency-band-per-epoch measurements, which we find to agree with theory and previous literature. We find a strong correlation between arc asymmetry and arc curvature, which we have replicated using simulations, and attribute to a bias in the Hough transform approach to scintillation arc analysis. Possible evidence for an approximately week long timescale over which a given scattering screen dominates signal propagation was found by tracking visible scintillation arcs in each epoch in PSR J1136+1551. The inclusion of a 155 minute observation allowed us to resolve the scale of scintillation variations on short timescales, which we find to be directly tied to the amount of ISM sampled over the observation. Some of our pulsars showed either consistent or emerging asymmetries in arc curvature, indicating instances of refraction across their lines of sight. Significant features in various pulsars, such as multiple scintillation arcs in PSR J1136+1551 and flat arclets in PSR J1509+5531, that have been found in previous works, were also detected. The simultaneous multiple band observing capability of the upgraded GMRT shows excellent promise for future pulsar scintillation work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05306v4-abstract-full').style.display = 'none'; document.getElementById('2301.05306v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2210.16633">arXiv:2210.16633</a> <span> [<a href="https://arxiv.org/pdf/2210.16633">pdf</a>, <a href="https://arxiv.org/ps/2210.16633">ps</a>, <a href="https://arxiv.org/format/2210.16633">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> </div> <p class="title is-5 mathjax"> Probing the Plasma Tail of Interstellar Comet 2I/Borisov </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P K Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Perillat%2C+P">Phil Perillat</a>, <a href="/search/astro-ph?searchtype=author&query=Salter%2C+C+J">C J Salter</a>, <a href="/search/astro-ph?searchtype=author&query=Ghosh%2C+T">Tapasi Ghosh</a>, <a href="/search/astro-ph?searchtype=author&query=Raizada%2C+S">Shikha Raizada</a>, <a href="/search/astro-ph?searchtype=author&query=Lynch%2C+R+S">Ryan S Lynch</a>, <a href="/search/astro-ph?searchtype=author&query=Bonsall-Pisano%2C+A">Amber Bonsall-Pisano</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B C Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Roshi%2C+A">Anish Roshi</a>, <a href="/search/astro-ph?searchtype=author&query=Brum%2C+C">Christiano Brum</a>, <a href="/search/astro-ph?searchtype=author&query=Venkataraman%2C+A">Arun Venkataraman</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2210.16633v1-abstract-short" style="display: inline;"> We present an occultation study of compact radio sources by the plasma tail of interstellar Comet 2I/Borisov (C/2019 Q4) both pre- and near-perihelion using the Arecibo and Green Bank radio telescopes. The interplanetary scintillation (IPS) technique was used to probe the plasma tail at P-band (302--352 MHz), 820 MHz, and L-band (1120--1730 MHz). The presence and absence of scintillation at differ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.16633v1-abstract-full').style.display = 'inline'; document.getElementById('2210.16633v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2210.16633v1-abstract-full" style="display: none;"> We present an occultation study of compact radio sources by the plasma tail of interstellar Comet 2I/Borisov (C/2019 Q4) both pre- and near-perihelion using the Arecibo and Green Bank radio telescopes. The interplanetary scintillation (IPS) technique was used to probe the plasma tail at P-band (302--352 MHz), 820 MHz, and L-band (1120--1730 MHz). The presence and absence of scintillation at different perpendicular distances from the central axis of the plasma tail suggests a narrow tail of less than 6~arcmin at a distance of $\sim$10~arcmin ($\sim$$10^6$~km) from the comet nucleus. Data recorded during the occultation of B1019+083 on 31 October 2019 with the Arecibo Telescope covered the width of the plasma tail from its outer region to the central axis. The systematic increase in scintillation during the occultation provides the plasma properties associated with the tail when the comet was at its pre-perihelion phase. The excess level of L-band scintillation indicates a plasma density enhancement of $\sim$15--20 times that of the background solar wind. The evolving shape of the observed scintillation power spectra across the tail from its edge to the central axis suggests a density spectrum flatter than Kolmogorov, and that the plasma-density irregularity scales present in the tail range between 10 and 700 km. The discovery of a high-frequency spectral excess, corresponding to irregularity scales much smaller than the Fresnel scale, suggests the presence of small-scale density structures in the plasma tail, likely caused by interaction between the solar wind and the plasma environment formed by the comet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2210.16633v1-abstract-full').style.display = 'none'; document.getElementById('2210.16633v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 10 figures, and 1 table (Accepted for publication in Planetary Science Journal)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.06070">arXiv:2208.06070</a> <span> [<a href="https://arxiv.org/pdf/2208.06070">pdf</a>, <a href="https://arxiv.org/format/2208.06070">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Physics Education">physics.ed-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1119/5.0065381">10.1119/5.0065381 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Bose Horn Antenna Radio Telescope (BHARAT) design for 21 cm hydrogen line experiments for radio astronomy teaching </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mhaske%2C+A+A">Ashish A. Mhaske</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+J">Joydeep Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Jacob%2C+J">Joe Jacob</a>, <a href="/search/astro-ph?searchtype=author&query=T%2C+P+K">Paul K. T</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2208.06070v1-abstract-short" style="display: inline;"> We have designed a low-cost radio telescope system named the Bose Horn Antenna Radio Telescope (BHARAT) to detect the 21 cm hydrogen line emission from our Galaxy. The system is being used at the Radio Physics Laboratory (RPL), Inter-University Centre for Astronomy and Astrophysics (IUCAA), India, for laboratory sessions and training students and teachers. It is also a part of the laboratory curri… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.06070v1-abstract-full').style.display = 'inline'; document.getElementById('2208.06070v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.06070v1-abstract-full" style="display: none;"> We have designed a low-cost radio telescope system named the Bose Horn Antenna Radio Telescope (BHARAT) to detect the 21 cm hydrogen line emission from our Galaxy. The system is being used at the Radio Physics Laboratory (RPL), Inter-University Centre for Astronomy and Astrophysics (IUCAA), India, for laboratory sessions and training students and teachers. It is also a part of the laboratory curriculum at several universities and colleges. Here, we present the design of a highly efficient, easy to build, and cost-effective dual-mode conical horn used as a radio telescope and describe the calibration procedure. We also present some model observation data acquired using the telescope for facilitating easy incorporation of this experiment in the laboratory curriculum of undergraduate or post-graduate programs. We have named the antenna after Acharya Jagadish Chandra Bose, honoring a pioneer in radio-wave science and an outstanding teacher, who inspired several world renowned scientists. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.06070v1-abstract-full').style.display = 'none'; document.getElementById('2208.06070v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 11 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in American Journal of Physics. 22 pages, 16 figures, and 1 table. Comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.06461">arXiv:2207.06461</a> <span> [<a href="https://arxiv.org/pdf/2207.06461">pdf</a>, <a href="https://arxiv.org/format/2207.06461">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s12036-022-09869-w">10.1007/s12036-022-09869-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Nanohertz Gravitational Wave Astronomy during the SKA Era: An InPTA perspective </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">Achamveedu Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Pandian%2C+A">Arul Pandian</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">Thiagaraj Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+P">Prerna Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Agarwal%2C+N">Nikita Agarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">Paramasivan Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Banik%2C+S">Sarmistha Banik</a>, <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Kato%2C+R">Ryo Kato</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a> , et al. (12 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.06461v1-abstract-short" style="display: inline;"> Decades long monitoring of millisecond pulsars, which exhibit highly stable rotational periods, in pulsar timing array experiments is on the threshold of discovering nanohertz stochastic gravitational wave background. This paper describes the Indian Pulsar timing array (InPTA) experiment, which employs the upgraded Giant Metrewave Radio Telescope (uGMRT) for timing an ensemble of millisecond pulsa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06461v1-abstract-full').style.display = 'inline'; document.getElementById('2207.06461v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.06461v1-abstract-full" style="display: none;"> Decades long monitoring of millisecond pulsars, which exhibit highly stable rotational periods, in pulsar timing array experiments is on the threshold of discovering nanohertz stochastic gravitational wave background. This paper describes the Indian Pulsar timing array (InPTA) experiment, which employs the upgraded Giant Metrewave Radio Telescope (uGMRT) for timing an ensemble of millisecond pulsars for this purpose. We highlight InPTA's observation strategies and analysis methods, which are relevant for a future PTA experiment with the more sensitive Square Kilometer Array (SKA) telescope. We show that the unique multi-sub-array multi-band wide-bandwidth frequency coverage of the InPTA provides Dispersion Measure estimates with unprecedented precision for PTA pulsars, e.g., ~ 2 x 10{-5} pc-cm{-3} for PSR J1909-3744. Configuring the SKA-low and SKA-mid as two and four sub-arrays respectively, it is shown that comparable precision is achievable, using observation strategies similar to those pursued by the InPTA, for a larger sample of 62 pulsars requiring about 26 and 7 hours per epoch for the SKA-mid and the SKA-low telescopes respectively. We also review the ongoing efforts to develop PTA-relevant general relativistic constructs that will be required to search for nanohertz gravitational waves from isolated super-massive black hole binary systems like blazar OJ 287. These efforts should be relevant to pursue persistent multi-messenger gravitational wave astronomy during the forthcoming era of the SKA telescope, the Thirty Meter Telescope, and the next-generation Event Horizon Telescope. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06461v1-abstract-full').style.display = 'none'; document.getElementById('2207.06461v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Journal of Astronomy and Astrophysics for Special Issue on Indian Participation in the SKA (Editors : Abhirup Datta, Nirupam Roy, Preeti Kharb and Tirthankar Roy Choudhury)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.06446">arXiv:2207.06446</a> <span> [<a href="https://arxiv.org/pdf/2207.06446">pdf</a>, <a href="https://arxiv.org/format/2207.06446">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s12036-022-09874-z">10.1007/s12036-022-09874-z <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pulsar timing irregularities and the Neutron Star interior in the era of SKA: An Indian Outlook </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Bandyopadhyay%2C+D">Debades Bandyopadhyay</a>, <a href="/search/astro-ph?searchtype=author&query=Grover%2C+H">Himanshu Grover</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a>, <a href="/search/astro-ph?searchtype=author&query=Banik%2C+S">Sarmistha Banik</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.06446v1-abstract-short" style="display: inline;"> There are two types of timing irregularities seen in pulsars: glitches and timing noise. Both of these phenomena can help us probe the interior of such exotic objects. This article presents a brief overview of the observational and theoretical aspects of pulsar timing irregularities and the main results from the investigations of these phenomena in India. The relevance of such Indian programs for… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06446v1-abstract-full').style.display = 'inline'; document.getElementById('2207.06446v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.06446v1-abstract-full" style="display: none;"> There are two types of timing irregularities seen in pulsars: glitches and timing noise. Both of these phenomena can help us probe the interior of such exotic objects. This article presents a brief overview of the observational and theoretical aspects of pulsar timing irregularities and the main results from the investigations of these phenomena in India. The relevance of such Indian programs for monitoring of young pulsars with the Square Kilometer Array (SKA) is presented, highlighting possible contributions of the Indian neutron star community to the upcoming SKA endeavour. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.06446v1-abstract-full').style.display = 'none'; document.getElementById('2207.06446v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">7 figure. Accepted for publication in the Journal of Astrophysics and Astronomy : SKA special issue</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.09289">arXiv:2206.09289</a> <span> [<a href="https://arxiv.org/pdf/2206.09289">pdf</a>, <a href="https://arxiv.org/format/2206.09289">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/pasa.2022.46">10.1017/pasa.2022.46 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Indian Pulsar Timing Array: First data release </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=K.%2C+N">Nobleson K.</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+P">Prerna Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Paladi%2C+A+K">Avinash Kumar Paladi</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Agarwal%2C+N">Nikita Agarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Ingale%2C+P">Prathamesh Ingale</a>, <a href="/search/astro-ph?searchtype=author&query=Kato%2C+R">Ryo Kato</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Marmat%2C+P">Piyush Marmat</a>, <a href="/search/astro-ph?searchtype=author&query=Pandian%2C+B+A">B. Arul Pandian</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T. Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Srivastava%2C+A">Aman Srivastava</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M">Mayuresh Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Susarla%2C+S+C">Sai Chaitanya Susarla</a> , et al. (13 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.09289v3-abstract-short" style="display: inline;"> We present the pulse arrival times and high-precision dispersion measure estimates for 14 millisecond pulsars observed simultaneously in the 300-500 MHz and 1260-1460 MHz frequency bands using the upgraded Giant Metrewave Radio Telescope (uGMRT). The data spans over a baseline of 3.5 years (2018-2021), and is the first official data release made available by the Indian Pulsar Timing Array collabor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.09289v3-abstract-full').style.display = 'inline'; document.getElementById('2206.09289v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.09289v3-abstract-full" style="display: none;"> We present the pulse arrival times and high-precision dispersion measure estimates for 14 millisecond pulsars observed simultaneously in the 300-500 MHz and 1260-1460 MHz frequency bands using the upgraded Giant Metrewave Radio Telescope (uGMRT). The data spans over a baseline of 3.5 years (2018-2021), and is the first official data release made available by the Indian Pulsar Timing Array collaboration. This data release presents a unique opportunity for investigating the interstellar medium effects at low radio frequencies and their impact on the timing precision of pulsar timing array experiments. In addition to the dispersion measure time series and pulse arrival times obtained using both narrowband and wideband timing techniques, we also present the dispersion measure structure function analysis for selected pulsars. Our ongoing investigations regarding the frequency dependence of dispersion measures have been discussed. Based on the preliminary analysis for five millisecond pulsars, we do not find any conclusive evidence of chromaticity in dispersion measures. Data from regular simultaneous two-frequency observations are presented for the first time in this work. This distinctive feature leads us to the highest precision dispersion measure estimates obtained so far for a subset of our sample. Simultaneous multi-band uGMRT observations in Band 3 and Band 5 are crucial for high-precision dispersion measure estimation and for the prospect of expanding the overall frequency coverage upon the combination of data from the various Pulsar Timing Array consortia in the near future. Parts of the data presented in this work are expected to be incorporated into the upcoming third data release of the International Pulsar Timing Array. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.09289v3-abstract-full').style.display = 'none'; document.getElementById('2206.09289v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 18 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages, 21 figures, 3 tables. Published in PASA</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Publications of the Astronomical Society of Australia, Volume 39, 2022, e053 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.13006">arXiv:2201.13006</a> <span> [<a href="https://arxiv.org/pdf/2201.13006">pdf</a>, <a href="https://arxiv.org/format/2201.13006">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac68f1">10.3847/1538-4357/ac68f1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetar XTE J1810-197: Spectro-temporal evolution of average radio emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2201.13006v2-abstract-short" style="display: inline;"> We present the long-term spectro-temporal evolution of the average radio emission properties of the magnetar XTE J1810-197 (PSR J1809-1943) following its most recent outburst in late 2018. We report the results from two and a half years of monitoring campaign with the upgraded Giant Metrewave Radio Telescope carried out over the frequency range of 300 - 1450 MHz. Our observations show intriguing t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.13006v2-abstract-full').style.display = 'inline'; document.getElementById('2201.13006v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.13006v2-abstract-full" style="display: none;"> We present the long-term spectro-temporal evolution of the average radio emission properties of the magnetar XTE J1810-197 (PSR J1809-1943) following its most recent outburst in late 2018. We report the results from two and a half years of monitoring campaign with the upgraded Giant Metrewave Radio Telescope carried out over the frequency range of 300 - 1450 MHz. Our observations show intriguing time variability in the average profile width, flux density, spectral index and the broadband spectral shape. While the average profile width appears to gradually decrease at later epochs, the flux density shows multiple episodes of radio re-brightening over the course of our monitoring. Our systematic monitoring observations reveal that the radio spectrum has steepened over time, resulting in evolution from a magnetar-like to a more pulsar-like spectrum. A more detailed analysis reveals that the radio spectrum has a turnover, and this turnover shifts towards lower frequencies with time. We present the details of our analysis leading to these results, and discuss our findings in the context of magnetar radio emission mechanisms as well as potential manifestations of the intervening medium. We also briefly discuss whether an evolving spectral turnover could be an ubiquitous property of radio magnetars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.13006v2-abstract-full').style.display = 'none'; document.getElementById('2201.13006v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 January, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 6 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.06908">arXiv:2112.06908</a> <span> [<a href="https://arxiv.org/pdf/2112.06908">pdf</a>, <a href="https://arxiv.org/format/2112.06908">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stac532">10.1093/mnras/stac532 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Low-frequency wideband timing of InPTA pulsars observed with the uGMRT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nobleson%2C+K">K Nobleson</a>, <a href="/search/astro-ph?searchtype=author&query=Agarwal%2C+N">Nikita Agarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Pandian%2C+A">Arul Pandian</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M A Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Pennucci%2C+T+T">Timothy T Pennucci</a>, <a href="/search/astro-ph?searchtype=author&query=Banik%2C+S">Sarmistha Banik</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Choudhary%2C+A">Arpita Choudhary</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Kato%2C+R">Ryo Kato</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Marmat%2C+P">Piyush Marmat</a> , et al. (7 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2112.06908v3-abstract-short" style="display: inline;"> High-precision measurements of the pulsar dispersion measure (DM) are possible using telescopes with low-frequency wideband receivers. We present an initial study of the application of the wideband timing technique, which can simultaneously measure the pulsar times of arrival (ToAs) and DMs, for a set of five pulsars observed with the upgraded Giant Metrewave Radio Telescope (uGMRT) as part of the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06908v3-abstract-full').style.display = 'inline'; document.getElementById('2112.06908v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.06908v3-abstract-full" style="display: none;"> High-precision measurements of the pulsar dispersion measure (DM) are possible using telescopes with low-frequency wideband receivers. We present an initial study of the application of the wideband timing technique, which can simultaneously measure the pulsar times of arrival (ToAs) and DMs, for a set of five pulsars observed with the upgraded Giant Metrewave Radio Telescope (uGMRT) as part of the Indian Pulsar Timing Array (InPTA) campaign. We have used the observations with the 300-500 MHz band of the uGMRT for this purpose. We obtain high precision in DM measurements with precisions of the order 10^{-6}cm^{-3}pc. The ToAs obtained have sub-渭s precision and the root-mean-square of the post-fit ToA residuals are in the sub-渭s range. We find that the uncertainties in the DMs and ToAs obtained with this wideband technique, applied to low-frequency data, are consistent with the results obtained with traditional pulsar timing techniques and comparable to high-frequency results from other PTAs. This work opens up an interesting possibility of using low-frequency wideband observations for precision pulsar timing and gravitational wave detection with similar precision as high-frequency observations used conventionally. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.06908v3-abstract-full').style.display = 'none'; document.getElementById('2112.06908v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 December, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.02382">arXiv:2111.02382</a> <span> [<a href="https://arxiv.org/pdf/2111.02382">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac6cee">10.3847/1538-4357/ac6cee <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multiband Detection of Repeating FRB 20180916B </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sand%2C+K+R">Ketan R. Sand</a>, <a href="/search/astro-ph?searchtype=author&query=Faber%2C+J">Jakob Faber</a>, <a href="/search/astro-ph?searchtype=author&query=Gajjar%2C+V">Vishal Gajjar</a>, <a href="/search/astro-ph?searchtype=author&query=Michilli%2C+D">Daniele Michilli</a>, <a href="/search/astro-ph?searchtype=author&query=Andersen%2C+B+C">Bridget C. Andersen</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kudale%2C+S">Sanjay Kudale</a>, <a href="/search/astro-ph?searchtype=author&query=Pilia%2C+M">Maura Pilia</a>, <a href="/search/astro-ph?searchtype=author&query=Brzycki%2C+B">Bryan Brzycki</a>, <a href="/search/astro-ph?searchtype=author&query=Cassanelli%2C+T">Tomas Cassanelli</a>, <a href="/search/astro-ph?searchtype=author&query=Croft%2C+S">Steve Croft</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+B">Biprateep Dey</a>, <a href="/search/astro-ph?searchtype=author&query=John%2C+H">Hoang John</a>, <a href="/search/astro-ph?searchtype=author&query=Leung%2C+C">Calvin Leung</a>, <a href="/search/astro-ph?searchtype=author&query=Mckinven%2C+R">Ryan Mckinven</a>, <a href="/search/astro-ph?searchtype=author&query=Ng%2C+C">Cherry Ng</a>, <a href="/search/astro-ph?searchtype=author&query=Pearlman%2C+A+B">Aaron B. Pearlman</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">Emily Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Price%2C+D+C">Danny C. Price</a>, <a href="/search/astro-ph?searchtype=author&query=Siemion%2C+A">Andrew Siemion</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+K">Kendrick Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Tendulkar%2C+S+P">Shriharsh P. Tendulkar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2111.02382v2-abstract-short" style="display: inline;"> We present a multiband study of FRB 20180916B, a repeating source with a 16.3 day periodicity. We report the detection of 4, 1 and 7 bursts from observations spanning 3 days using upgraded Giant Metrewave Radio Telescope (300-500 MHz), Canadian Hydrogen Intensity Mapping Experiment (400-800 MHz) and Green Bank Telescope (600-1000 MHz), respectively. We report the first-ever detection of the source… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.02382v2-abstract-full').style.display = 'inline'; document.getElementById('2111.02382v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.02382v2-abstract-full" style="display: none;"> We present a multiband study of FRB 20180916B, a repeating source with a 16.3 day periodicity. We report the detection of 4, 1 and 7 bursts from observations spanning 3 days using upgraded Giant Metrewave Radio Telescope (300-500 MHz), Canadian Hydrogen Intensity Mapping Experiment (400-800 MHz) and Green Bank Telescope (600-1000 MHz), respectively. We report the first-ever detection of the source in the 800-1000 MHz range along with one of the widest instantaneous bandwidth detection (200 MHz) at lower frequencies. We identify 30 $渭$s wide structures in one of the bursts at 800 MHz, making it the lowest frequency detection of such structures for this FRB thus far. There is also a clear indication of high activity of the source at a higher frequency during earlier phases of the activity cycle. We identify a gradual decrease in the rotation measure over two years and no significant variations in the dispersion measure. We derive useful conclusions about progenitor scenarios, energy distribution, emission mechanisms, and variation of downward drift rate of emission with frequency. Our results reinforce that multiband observations are an effective approach to study repeaters and even one-off events to better understand their varying activity and spectral anomalies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.02382v2-abstract-full').style.display = 'none'; document.getElementById('2111.02382v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 10 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 932 98 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2107.04607">arXiv:2107.04607</a> <span> [<a href="https://arxiv.org/pdf/2107.04607">pdf</a>, <a href="https://arxiv.org/format/2107.04607">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnrasl/slab098">10.1093/mnrasl/slab098 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence for profile changes in PSR J1713+0747 using the uGMRT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Tarafdar%2C+P">Pratik Tarafdar</a>, <a href="/search/astro-ph?searchtype=author&query=Rana%2C+P">Prerna Rana</a>, <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Kolhe%2C+N">Neel Kolhe</a>, <a href="/search/astro-ph?searchtype=author&query=Agarwal%2C+N">Nikita Agarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Bathula%2C+A">Adarsh Bathula</a>, <a href="/search/astro-ph?searchtype=author&query=Dandapat%2C+S">Subhajit Dandapat</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Hisano%2C+S">Shinnosuke Hisano</a>, <a href="/search/astro-ph?searchtype=author&query=Kato%2C+R">Ryo Kato</a>, <a href="/search/astro-ph?searchtype=author&query=Kharbanda%2C+D">Divyansh Kharbanda</a>, <a href="/search/astro-ph?searchtype=author&query=Kikunaga%2C+T">Tomonosuke Kikunaga</a>, <a href="/search/astro-ph?searchtype=author&query=Marmat%2C+P">Piyush Marmat</a>, <a href="/search/astro-ph?searchtype=author&query=Susarla%2C+S+C">Sai Chaitanya Susarla</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Choudhury%2C+A">Arpita Choudhury</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a> , et al. (7 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2107.04607v2-abstract-short" style="display: inline;"> PSR J1713+0747 is one of the most precisely timed pulsars in the international pulsar timing array experiment. This pulsar showed an abrupt profile shape change between April 16, 2021 (MJD 59320) and April 17, 2021 (MJD 59321). In this paper, we report the results from multi-frequency observations of this pulsar carried out with the upgraded Giant Metrewave Radio Telescope (uGMRT) before and after… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.04607v2-abstract-full').style.display = 'inline'; document.getElementById('2107.04607v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2107.04607v2-abstract-full" style="display: none;"> PSR J1713+0747 is one of the most precisely timed pulsars in the international pulsar timing array experiment. This pulsar showed an abrupt profile shape change between April 16, 2021 (MJD 59320) and April 17, 2021 (MJD 59321). In this paper, we report the results from multi-frequency observations of this pulsar carried out with the upgraded Giant Metrewave Radio Telescope (uGMRT) before and after the event. We demonstrate the profile change seen in Band 5 (1260 MHz - 1460 MHz) and Band 3 (300 MHz - 500 MHz). The timing analysis of this pulsar shows a disturbance accompanying this profile change followed by a recovery with a timescale of $\sim 159$ days. Our data suggest that a model with chromatic index as a free parameter is preferred over models with combinations of achromaticity with DM bump or scattering bump. We determine the frequency dependence to be $\sim谓^{+1.34}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2107.04607v2-abstract-full').style.display = 'none'; document.getElementById('2107.04607v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 August, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS-Letters</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.01942">arXiv:2106.01942</a> <span> [<a href="https://arxiv.org/pdf/2106.01942">pdf</a>, <a href="https://arxiv.org/format/2106.01942">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stab1640">10.1093/mnras/stab1640 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A real-time Automated Glitch Detection Pipeline at Ooty Radio Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugam%2C+P">P. Arumugam</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.01942v2-abstract-short" style="display: inline;"> Glitches are the observational manifestations of superfluidity inside neutron stars. The aim of this paper is to describe an automated glitch detection pipeline, which can alert the observers on possible real-time detection of rotational glitches in pulsars. Post alert, the pulsars can be monitored at a higher cadence to measure the post-glitch recovery phase. Two algorithms namely, Median Absolut… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.01942v2-abstract-full').style.display = 'inline'; document.getElementById('2106.01942v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.01942v2-abstract-full" style="display: none;"> Glitches are the observational manifestations of superfluidity inside neutron stars. The aim of this paper is to describe an automated glitch detection pipeline, which can alert the observers on possible real-time detection of rotational glitches in pulsars. Post alert, the pulsars can be monitored at a higher cadence to measure the post-glitch recovery phase. Two algorithms namely, Median Absolute Deviation (MAD) and polynomial regression have been explored to detect glitches in real time. The pipeline has been optimized with the help of simulated timing residuals for both the algorithms. Based on the simulations, we conclude that the polynomial regression algorithm is significantly more effective for real time glitch detection. The pipeline has been tested on a few published glitches. This pipeline is presently implemented at the Ooty Radio Telescope. In the era of upcoming large telescopes like SKA, several hundreds of pulsars will be observed regularly and such a tool will be useful for both real-time detection as well as optimal utilization of observation time for such glitching pulsars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.01942v2-abstract-full').style.display = 'none'; document.getElementById('2106.01942v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 6 figures, Accepted for publication in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Monthly Notices of the Royal Astronomical Society, 505, 4, 2021, 5488-5496 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.03606">arXiv:2102.03606</a> <span> [<a href="https://arxiv.org/pdf/2102.03606">pdf</a>, <a href="https://arxiv.org/format/2102.03606">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s12036-021-09748-w">10.1007/s12036-021-09748-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Absolute Time Calibration of LAXPC aboard AstroSat </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+D">Dipankar Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.03606v1-abstract-short" style="display: inline;"> The AstroSat mission carries several high-energy detectors meant for fast timing studies of cosmic sources. In order to carry out high precision multi-wavelength timing studies, it is essential to calibrate the absolute time stamps of these instruments to the best possible accuracy. We present here the absolute time calibration of the AstroSat LAXPC instrument, utilising the broadband electromagne… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.03606v1-abstract-full').style.display = 'inline'; document.getElementById('2102.03606v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.03606v1-abstract-full" style="display: none;"> The AstroSat mission carries several high-energy detectors meant for fast timing studies of cosmic sources. In order to carry out high precision multi-wavelength timing studies, it is essential to calibrate the absolute time stamps of these instruments to the best possible accuracy. We present here the absolute time calibration of the AstroSat LAXPC instrument, utilising the broadband electromagnetic emission from the Crab Pulsar to cross calibrate against Fermi-LAT and ground based radio observatories Giant Metrewave Radio Telescope (GMRT) and the Ooty Radio Telescope (ORT). Using the techniques of pulsar timing, we determine the fixed timing offsets of LAXPC with respect to these different instruments and also compare the offsets with those of another AstroSat instrument, CZTI. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.03606v1-abstract-full').style.display = 'none'; document.getElementById('2102.03606v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 6 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 2 figures, 2 tables. Accepted for publication in the Journal of Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2101.05334">arXiv:2101.05334</a> <span> [<a href="https://arxiv.org/pdf/2101.05334">pdf</a>, <a href="https://arxiv.org/format/2101.05334">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202140340">10.1051/0004-6361/202140340 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High Precision Measurements of Interstellar Dispersion Measure with the upgraded GMRT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Nobleson%2C+K">K. Nobleson</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Susarla%2C+S+C">Sai Chaitanya Susarla</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A. Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Choudhary%2C+A">Arpita Choudhary</a>, <a href="/search/astro-ph?searchtype=author&query=De%2C+K">Kishalay De</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A+K">Arun Kumar Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Pathak%2C+D">Dhruv Pathak</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T. Prabu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2101.05334v4-abstract-short" style="display: inline;"> Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density along the line of sight. Correcting for this delay accurately is crucial for the detection of nanohertz gravitational waves using Pulsar Timing Arrays. In this wo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.05334v4-abstract-full').style.display = 'inline'; document.getElementById('2101.05334v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2101.05334v4-abstract-full" style="display: none;"> Pulsar radio emission undergoes dispersion due to the presence of free electrons in the interstellar medium (ISM). The dispersive delay in the arrival time of pulsar signal changes over time due to the varying ISM electron column density along the line of sight. Correcting for this delay accurately is crucial for the detection of nanohertz gravitational waves using Pulsar Timing Arrays. In this work, we present in-band and inter-band DM estimates of four pulsars observed with uGMRT over the timescale of a year using two different template alignment methods. The DMs obtained using both these methods show only subtle differences for PSR 1713+0747 and J1909$-$3744. A considerable offset is seen in the DM of PSR J1939+2134 and J2145$-$0750 between the two methods. This could be due to the presence of scattering in the former and profile evolution in the latter. We find that both methods are useful but could have a systematic offset between the DMs obtained. Irrespective of the template alignment methods followed, the precision on the DMs obtained is about $10^{-3}$ pc cm$^{-3}$ using only BAND3 and $10^{-4}$ pc cm$^{-3}$ after combining data from BAND3 and BAND5 of the uGMRT. In a particular result, we have detected a DM excess of about $5\times10^{-3}$ pc cm$^{-3}$ on 24 February 2019 for PSR J2145$-$0750. This excess appears to be due to the interaction region created by fast solar wind from a coronal hole and a coronal mass ejection (CME) observed from the Sun on that epoch. A detailed analysis of this interesting event is presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2101.05334v4-abstract-full').style.display = 'none'; document.getElementById('2101.05334v4-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 6 figures, 2 tables. Accepted by A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 651, A5 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.02930">arXiv:2007.02930</a> <span> [<a href="https://arxiv.org/pdf/2007.02930">pdf</a>, <a href="https://arxiv.org/format/2007.02930">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/pasa.2021.12">10.1017/pasa.2021.12 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> pinta: The uGMRT Data Processing Pipeline for the Indian Pulsar Timing Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Prabu%2C+T">T. Prabu</a>, <a href="/search/astro-ph?searchtype=author&query=Desai%2C+S">Shantanu Desai</a>, <a href="/search/astro-ph?searchtype=author&query=Nobleson%2C+K">K. Nobleson</a>, <a href="/search/astro-ph?searchtype=author&query=Susarla%2C+S+C">Sai Chaitanya Susarla</a>, <a href="/search/astro-ph?searchtype=author&query=Girgaonkar%2C+R">Raghav Girgaonkar</a>, <a href="/search/astro-ph?searchtype=author&query=Dey%2C+L">Lankeswar Dey</a>, <a href="/search/astro-ph?searchtype=author&query=Batra%2C+N+D">Neelam Dhanda Batra</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A. Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Bethapudi%2C+S">Suryarao Bethapudi</a>, <a href="/search/astro-ph?searchtype=author&query=Choudhary%2C+A">Arpita Choudhary</a>, <a href="/search/astro-ph?searchtype=author&query=De%2C+K">Kishalay De</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A+K">Arun Kumar Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Pathak%2C+D">Dhruv Pathak</a>, <a href="/search/astro-ph?searchtype=author&query=Singha%2C+J">Jaikhomba Singha</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2007.02930v5-abstract-short" style="display: inline;"> We introduce pinta, a pipeline for reducing the upgraded Giant Metre-wave Radio Telescope (uGMRT) raw pulsar timing data, developed for the Indian Pulsar Timing Array experiment. We provide a detailed description of the workflow and usage of pinta, as well as its computational performance and RFI mitigation characteristics. We also discuss a novel and independent determination of the relative time… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.02930v5-abstract-full').style.display = 'inline'; document.getElementById('2007.02930v5-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.02930v5-abstract-full" style="display: none;"> We introduce pinta, a pipeline for reducing the upgraded Giant Metre-wave Radio Telescope (uGMRT) raw pulsar timing data, developed for the Indian Pulsar Timing Array experiment. We provide a detailed description of the workflow and usage of pinta, as well as its computational performance and RFI mitigation characteristics. We also discuss a novel and independent determination of the relative time offsets between the different back-end modes of uGMRT and the interpretation of the uGMRT observation frequency settings, and their agreement with results obtained from engineering tests. Further, we demonstrate the capability of pinta to generate data products which can produce high-precision TOAs using PSR J1909-3744 as an example. These results are crucial for performing precision pulsar timing with the uGMRT. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.02930v5-abstract-full').style.display = 'none'; document.getElementById('2007.02930v5-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Publications of the Astronomical Society of Australia, 38, E017 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.04934">arXiv:1911.04934</a> <span> [<a href="https://arxiv.org/pdf/1911.04934">pdf</a>, <a href="https://arxiv.org/format/1911.04934">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stz3230">10.1093/mnras/stz3230 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observed glitches in 8 young pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+D">Dipankar Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Nandi%2C+R">Rana Nandi</a>, <a href="/search/astro-ph?searchtype=author&query=Bandyopadhyay%2C+D">Debades Bandyopadhyay</a>, <a href="/search/astro-ph?searchtype=author&query=Char%2C+P">Prasanta Char</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1911.04934v2-abstract-short" style="display: inline;"> The abrupt change in the pulse period of a pulsar is called a pulsar glitch. In this paper, we present eleven pulsar glitches detected using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT) in high cadence timing observations of 8 pulsars. The measured relative amplitude of glitches ($螖谓/谓$) from our data ranges from $10^{-6}$ to $10^{-9}$. Among these glitch… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.04934v2-abstract-full').style.display = 'inline'; document.getElementById('1911.04934v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.04934v2-abstract-full" style="display: none;"> The abrupt change in the pulse period of a pulsar is called a pulsar glitch. In this paper, we present eleven pulsar glitches detected using the Ooty Radio Telescope (ORT) and the upgraded Giant Metrewave Radio Telescope (uGMRT) in high cadence timing observations of 8 pulsars. The measured relative amplitude of glitches ($螖谓/谓$) from our data ranges from $10^{-6}$ to $10^{-9}$. Among these glitches, three are new discoveries, being reported for the first time. We also reanalyze the largest pulsar glitch in the Crab pulsar (PSR J0534+2200) by fitting the ORT data to a new phenomenological model including the slow rise in the post-glitch evolution. We measure an exponential recovery of 30 days after the Vela glitch detected on MJD 57734 with a healing factor $Q=5.8\times 10^{-3}$. Further, we report the largest glitch ($螖谓/谓= 3147.9 \times 10^{-9}$) so far in PSR J1731$-$4744. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.04934v2-abstract-full').style.display = 'none'; document.getElementById('1911.04934v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 12 figures, 3 tables; Accepted for publication in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, Vol 491, Issue 3, Jan 2020, pages 3182-3191 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.04304">arXiv:1908.04304</a> <span> [<a href="https://arxiv.org/pdf/1908.04304">pdf</a>, <a href="https://arxiv.org/ps/1908.04304">ps</a>, <a href="https://arxiv.org/format/1908.04304">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/ab3a47">10.3847/2041-8213/ab3a47 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Distinct properties of the radio burst emission from the magnetar XTE J1810-197 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.04304v2-abstract-short" style="display: inline;"> XTE J1810-197 (PSR J1809-1943) was the first ever magnetar which was found to emit transient radio emission. It has recently undergone another radio and high-energy outburst. This is only the second radio outburst that has been observed from this source. We observed J1810-197 soon after its recent radio outburst at low radio frequencies using the Giant Metrewave Radio Telescope. We present the 650… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.04304v2-abstract-full').style.display = 'inline'; document.getElementById('1908.04304v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.04304v2-abstract-full" style="display: none;"> XTE J1810-197 (PSR J1809-1943) was the first ever magnetar which was found to emit transient radio emission. It has recently undergone another radio and high-energy outburst. This is only the second radio outburst that has been observed from this source. We observed J1810-197 soon after its recent radio outburst at low radio frequencies using the Giant Metrewave Radio Telescope. We present the 650 MHz flux density evolution of the source in the early phases of the outburst, and its radio spectrum down to frequencies as low as 300 MHz. The magnetar also exhibits radio emission in the form of strong, narrow bursts. We show that the bursts have a characteristic intrinsic width of the order of 0.5-0.7 ms, and discuss their properties in the context of giant pulses and giant micropulses from other pulsars. We also show that the bursts exhibit spectral structures which cannot be explained by interstellar propagation effects. These structures might indicate a phenomenological link with the repeating fast radio bursts which also show interesting, more detailed frequency structures. While the spectral structures are particularly noticeable in the early phases of the outburst, these seem to be less prominent as well as less frequent in the later phases, suggesting an evolution of the underlying cause of these spectral structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.04304v2-abstract-full').style.display = 'none'; document.getElementById('1908.04304v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 September, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">A few minor changes in the previous version; consistent with the published article</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJL, 2019, vol. 882, L9 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1905.01651">arXiv:1905.01651</a> <span> [<a href="https://arxiv.org/pdf/1905.01651">pdf</a>, <a href="https://arxiv.org/ps/1905.01651">ps</a>, <a href="https://arxiv.org/format/1905.01651">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab20c5">10.3847/1538-4357/ab20c5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-frequency scatter broadening evolution of pulsars - II. Scatter broadening of nearby pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1905.01651v1-abstract-short" style="display: inline;"> We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the archival data from LOFAR and LWA. This study has increased the total of all multi-frequency or wide-band scattering measurements up to a dispersion measure (DM)… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.01651v1-abstract-full').style.display = 'inline'; document.getElementById('1905.01651v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.01651v1-abstract-full" style="display: none;"> We present multi-frequency scatter broadening evolution of 29 pulsars observed with the LOw Frequency ARray (LOFAR) and Long Wavelength Array (LWA). We conducted new observations using LOFAR Low Band Antennae (LBA) as well as utilized the archival data from LOFAR and LWA. This study has increased the total of all multi-frequency or wide-band scattering measurements up to a dispersion measure (DM) of 150~pc\,cm$^{-3}$ by 60\%. The scatter broadening timescale ($蟿_{sc}$) measurements at different frequencies are often combined by scaling them to a common reference frequency of 1\,GHz. Using our data, we show that the $蟿_{sc}$--DM variations are best fitted for reference frequencies close to 200--300\,MHz, and scaling to higher or lower frequencies results in significantly more scatter in data. We suggest that this effect might indicate a frequency dependence of the scatter broadening scaling index ($伪$). However, a selection bias due to our chosen observing frequencies can not be ruled out with the current data set. Our data did not favour any particular model of the DM -- $蟿_{sc}$ relations, and we do not see a statistically significant break at the low DM range in this relation. The turbulence spectral index ($尾$) is found to be steeper than that is expected from a Kolmogorov spectrum. This indicates that the local ISM turbulence may have a low wave-number cutoff or presence of large scale inhomogeneities in the line of sight to some of the reported pulsars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.01651v1-abstract-full').style.display = 'none'; document.getElementById('1905.01651v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.02907">arXiv:1811.02907</a> <span> [<a href="https://arxiv.org/pdf/1811.02907">pdf</a>, <a href="https://arxiv.org/format/1811.02907">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aaee7f">10.3847/1538-4357/aaee7f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Follow-up Timing of Three GMRT Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=McLaughlin%2C+M+A">Maura A. McLaughlin</a>, <a href="/search/astro-ph?searchtype=author&query=A.%2C+K+M">Krishnakumar M. A.</a>, <a href="/search/astro-ph?searchtype=author&query=K.%2C+M+P">Manoharan P. K.</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1811.02907v1-abstract-short" style="display: inline;"> We report on the results of multi-frequency follow-up observations of three pulsars (PSRs J0026+6320, J2208+5500 and J2217+5733) discovered with the Giant Metrewave Radio Telescope (GMRT). These observations were carried out with the GMRT and the Ooty Radio Telescope (ORT). We report improved timing solutions for all three pulsars. For PSR J2208+5500, we estimate the nulling fraction to be 53(3)\%… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02907v1-abstract-full').style.display = 'inline'; document.getElementById('1811.02907v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.02907v1-abstract-full" style="display: none;"> We report on the results of multi-frequency follow-up observations of three pulsars (PSRs J0026+6320, J2208+5500 and J2217+5733) discovered with the Giant Metrewave Radio Telescope (GMRT). These observations were carried out with the GMRT and the Ooty Radio Telescope (ORT). We report improved timing solutions for all three pulsars. For PSR J2208+5500, we estimate the nulling fraction to be 53(3)\%. The steep spectrum of this pulsar, its single component profile, and narrow pulse width suggest its single component to be a core component. If so, this significant cessation of emission in a core component is inconsistent with a geometric origin of nulls, such as those due to `empty' sightline traverses, and more likely due to intrinsic changes in the pulsar magnetosphere. We have measured scatter-broadening timescales at 325 and 610 MHz for PSRs J0026+6320 and J2217+5733. The implied scatter-broadening frequency scaling index of $-$2.9 for both pulsars is different from that expected assuming Kolmogorov turbulence in the interstellar medium. We also report spectral indices, obtained from imaging observations, for all three pulsars for the first time. The spectra for two of these pulsars indicate a possible spectral turnover between 100$-$300 MHz. Multi-frequency timing analyses carried out for these pulsars have enabled us to determine dispersion measures (DMs) with accuracies of 0.01 pc cm\sups{--3}. This demonstrates the usefulness of quasi-simultaneous multi-frequency multi-epoch timing observations with the GMRT and the ORT for studying variations in DM for millisecond pulsars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02907v1-abstract-full').style.display = 'none'; document.getElementById('1811.02907v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.02508">arXiv:1808.02508</a> <span> [<a href="https://arxiv.org/pdf/1808.02508">pdf</a>, <a href="https://arxiv.org/format/1808.02508">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty2177">10.1093/mnras/sty2177 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exploring the Effect of Periastron Advance in Small-Eccentricity Binary Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Susobhanan%2C+A">Abhimanyu Susobhanan</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">Achamveedu Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kumar%2C+R">Ranjan Kumar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1808.02508v1-abstract-short" style="display: inline;"> Short-orbital period small-eccentricity binary pulsars can, in principle, experience substantial advance of periastron. We explore the possibility of measuring this effect by implementing a timing model, ELL1k, in the popular TEMPO2 pulsar timing package. True secular variations in the Laplace-Lagrange parameters, present in our ELL1k model, can lead to measurable timing residuals while pursuing d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.02508v1-abstract-full').style.display = 'inline'; document.getElementById('1808.02508v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.02508v1-abstract-full" style="display: none;"> Short-orbital period small-eccentricity binary pulsars can, in principle, experience substantial advance of periastron. We explore the possibility of measuring this effect by implementing a timing model, ELL1k, in the popular TEMPO2 pulsar timing package. True secular variations in the Laplace-Lagrange parameters, present in our ELL1k model, can lead to measurable timing residuals while pursuing decade-long timing campaigns using the existing ELL1 timing model of Lange et al. (2001), especially for binaries exhibiting significant periastron advance. We also list the main differences between our approach and various implementations of the ELL1 model present in both TEMPO and TEMPO2 packages. Detailed TEMPO2 simulations suggest the possibility of constraining the apsidal motion constant of pulsar companions in certain observed binary pulsars with minuscule eccentricities such as PSR J1719-1438. Fortunately, the ELL1k timing model does not pose any challenges to the on-going Pulsar Timing Array campaigns that routinely employ the ELL1 timing model. Detailed TEMPO2 simulations suggest the possibility of constraining the apsidal motion constant of pulsar companions in certain observed binary pulsars with minuscule eccentricities such as PSR J1719-1438. Fortunately, the ELL1k timing model does not pose any challenges to the on-going Pulsar Timing Array campaigns that routinely employ the ELL1 timing model. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.02508v1-abstract-full').style.display = 'none'; document.getElementById('1808.02508v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2018. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.08363">arXiv:1807.08363</a> <span> [<a href="https://arxiv.org/pdf/1807.08363">pdf</a>, <a href="https://arxiv.org/ps/1807.08363">ps</a>, <a href="https://arxiv.org/format/1807.08363">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aad4ad">10.3847/1538-4357/aad4ad <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Search for Pulsars in Steep Spectrum Radio Sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C">Cees Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=van+Leeuwen%2C+J">Joeri van Leeuwen</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.08363v1-abstract-short" style="display: inline;"> We report on a time-domain search for pulsars in 44 steep spectrum radio sources originally identified from recent imaging surveys. The time-domain search was conducted at 327 MHz using the Ooty radio telescope, and utilized a semi-coherent dedispersion scheme retaining the sensitivity even for sub-millisecond periods up to reasonably high dispersion measures. No new pulsars were found. We discuss… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.08363v1-abstract-full').style.display = 'inline'; document.getElementById('1807.08363v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.08363v1-abstract-full" style="display: none;"> We report on a time-domain search for pulsars in 44 steep spectrum radio sources originally identified from recent imaging surveys. The time-domain search was conducted at 327 MHz using the Ooty radio telescope, and utilized a semi-coherent dedispersion scheme retaining the sensitivity even for sub-millisecond periods up to reasonably high dispersion measures. No new pulsars were found. We discuss the nature of these steep spectrum sources and argue that majority of the sources in our sample should either be pulsars or a new category of Galactic sources. Several possibilities that could hinder detection of these sources as pulsars, including anomalously high scattering or alignment of the rotation and magnetic axes, are discussed in detail, and we suggest unconventional search methods to further probe these possibilities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.08363v1-abstract-full').style.display = 'none'; document.getElementById('1807.08363v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.01521">arXiv:1806.01521</a> <span> [<a href="https://arxiv.org/pdf/1806.01521">pdf</a>, <a href="https://arxiv.org/format/1806.01521">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Theory">nucl-th</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aaddf4">10.3847/1538-4357/aaddf4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Glitch Behavior of Pulsars and Contribution from Neutron Star Crust </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Char%2C+P">Prasanta Char</a>, <a href="/search/astro-ph?searchtype=author&query=Nandi%2C+R">Rana Nandi</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Bandyopadhyay%2C+D">Debades Bandyopadhyay</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1806.01521v2-abstract-short" style="display: inline;"> Pulsars are highly magnetized rotating neutron stars with a very stable rotation speed. Irrespective of their stable rotation rate, many pulsars have been observed with the sudden jump in the rotation rate, which is known as pulsar glitch. The glitch phenomena are considered to be an exhibit of superfluidity of neutron matter inside the neutron star's crustal region. The magnitude of such rapid ch… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.01521v2-abstract-full').style.display = 'inline'; document.getElementById('1806.01521v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.01521v2-abstract-full" style="display: none;"> Pulsars are highly magnetized rotating neutron stars with a very stable rotation speed. Irrespective of their stable rotation rate, many pulsars have been observed with the sudden jump in the rotation rate, which is known as pulsar glitch. The glitch phenomena are considered to be an exhibit of superfluidity of neutron matter inside the neutron star's crustal region. The magnitude of such rapid change in rotation rate relative to their stable rotation frequency can quantify the moment of inertia of the crustal region to the total moment of inertia of the star called as the fractional moment of inertia (FMI). In this paper, we have calculated FMI for different masses of the star using six different representative unified equations of state (EoS) constructed under Relativistic Mean Field (RMF) framework. We have performed an event-wise comparison of FMI obtained from data with that of theoretically calculated values with and without considering the entrainment effect. It is found that larger glitches can't be explained by crustal FMI alone, even without the entrainment. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.01521v2-abstract-full').style.display = 'none'; document.getElementById('1806.01521v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 29 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 3 figures, 1 table, revised, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1806.01066">arXiv:1806.01066</a> <span> [<a href="https://arxiv.org/pdf/1806.01066">pdf</a>, <a href="https://arxiv.org/format/1806.01066">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201832913">10.1051/0004-6361/201832913 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Timing Offset Calibration of CZTI instrument aboard ASTROSAT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Basu%2C+A">Avishek Basu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+D">Dipankar Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Rao%2C+A+R">A R Rao</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">A. Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Arumugsamy%2C+P">Prakash Arumugsamy</a>, <a href="/search/astro-ph?searchtype=author&query=Vadawale%2C+S">Santosh Vadawale</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Dewangan%2C+G+C">G. C. Dewangan</a>, <a href="/search/astro-ph?searchtype=author&query=Vibhute%2C+A">Ajay Vibhute</a>, <a href="/search/astro-ph?searchtype=author&query=Mithun%2C+N+P+S">N. P. S. Mithun</a>, <a href="/search/astro-ph?searchtype=author&query=Sharma%2C+V">Vidushi Sharma</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1806.01066v2-abstract-short" style="display: inline;"> The radio as well as the high energy emission mechanism in pulsars is yet not understood properly. A multi-wavelength study is likely to help in better understanding of such processes. The first Indian space-based observatory, ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum from infra-red (1300 $脜$) to hard X-ray (380 KeV). Cadmium Zinc Telluride Imager (CZTI), one… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.01066v2-abstract-full').style.display = 'inline'; document.getElementById('1806.01066v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.01066v2-abstract-full" style="display: none;"> The radio as well as the high energy emission mechanism in pulsars is yet not understood properly. A multi-wavelength study is likely to help in better understanding of such processes. The first Indian space-based observatory, ASTROSAT, has five instruments aboard, which cover the electromagnetic spectrum from infra-red (1300 $脜$) to hard X-ray (380 KeV). Cadmium Zinc Telluride Imager (CZTI), one of the five instruments is a hard X-ray telescope functional over an energy range of 20-380 KeV. We aim to estimate the timing offset introduced in the data acquisition pipeline of the instrument, which will help in time alignment of high energy time series with those from two other ground-based observatories, viz. the Giant Meterwave Radio Telescope (GMRT) and the Ooty Radio Telescope (ORT). PSR B0531+21 is a well-studied pulsar with nearly aligned radio and hard X-ray pulse profiles. We use simultaneous observations of this pulsar with the ASTROSAT, the ORT and the GMRT. The pulsar was especially observed using the ORT with almost daily cadence to obtain good timing solutions. We also supplement the ORT data with archival FERMI data for estimation of timing noise. The timing offset of ASTROSAT instruments was estimated from fits to arrival time data at the ASTROSAT and the radio observatories. We estimate the offset between the GMRT and the ASTROSAT-CZTI to be -4716 $\pm$ 50 $渭s$. The corresponding offset with the ORT was -29639 $\pm$ 50 $渭s$. The offsets between the GMRT and Fermi-LAT -5368 $\pm$ 56 $渭s$. (Abridged) <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.01066v2-abstract-full').style.display = 'none'; document.getElementById('1806.01066v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">6 pages, 5 figures, 2 tables, Revised and Updated, accepted for publication in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 617, A22 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.05260">arXiv:1805.05260</a> <span> [<a href="https://arxiv.org/pdf/1805.05260">pdf</a>, <a href="https://arxiv.org/ps/1805.05260">ps</a>, <a href="https://arxiv.org/format/1805.05260">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/sty1301">10.1093/mnras/sty1301 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> GMRT Galactic Plane Pulsar and Transient Survey and the Discovery of PSR J1838+1523 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">Mayuresh P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=McLaughlin%2C+M+A">Maura A. McLaughlin</a>, <a href="/search/astro-ph?searchtype=author&query=Lorimer%2C+D+R">Duncan R. Lorimer</a>, <a href="/search/astro-ph?searchtype=author&query=A.%2C+K+M">Krishnakumar M. A.</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1805.05260v1-abstract-short" style="display: inline;"> We report the results of a blind pulsar survey carried out with the Giant Metrewave Radio Telescope (GMRT) at 325 MHz. The survey covered about 10\% of the region between Galactic longitude 45$^{\circ} < l <$ 135$^{\circ}$ and Galactic latitude 1$^{\circ} < |b| <$ 10$^{\circ}$ with a dwell time of 1800 s, resulting in the detection of 28 pulsars. One of these, PSR J1838+1523, was previously unknow… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.05260v1-abstract-full').style.display = 'inline'; document.getElementById('1805.05260v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.05260v1-abstract-full" style="display: none;"> We report the results of a blind pulsar survey carried out with the Giant Metrewave Radio Telescope (GMRT) at 325 MHz. The survey covered about 10\% of the region between Galactic longitude 45$^{\circ} < l <$ 135$^{\circ}$ and Galactic latitude 1$^{\circ} < |b| <$ 10$^{\circ}$ with a dwell time of 1800 s, resulting in the detection of 28 pulsars. One of these, PSR J1838+1523, was previously unknown and has a period of 549 ms and a dispersion measure of 68 pc cm\sups{$-$3}. We also present the timing solution of this pulsar obtained from multi-frequency timing observations carried out with the GMRT and the Ooty Radio Telescope. The measured flux density of this pulsar is 4.3$\pm$1.8 and 1.2$\pm$0.7 mJy at 325 and 610 MHz, respectively. This implies a spectral index of $-$2$\pm$0.8, thus making the expected flux density at 1.4 GHz to be about 0.2 mJy, which would be just detectable in the high frequency pulsar surveys like the Northern High Time Resolution Universe pulsar survey. This discovery underlines the importance of low frequency pulsar surveys in detecting steep spectrum pulsars, thus providing complementary coverage of the pulsar population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.05260v1-abstract-full').style.display = 'none'; document.getElementById('1805.05260v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.04455">arXiv:1712.04455</a> <span> [<a href="https://arxiv.org/pdf/1712.04455">pdf</a>, <a href="https://arxiv.org/format/1712.04455">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx3284">10.1093/mnras/stx3284 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of long nulls in PSR B1706$-$16, a pulsar with large timing irregularities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A Krishnakumar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1712.04455v1-abstract-short" style="display: inline;"> Single pulse observations, characterizing in detail, the nulling behaviour of PSR B1706$-$16 are being reported for the first time in this paper. Our regular long duration monitoring of this pulsar reveals long nulls of 2 to 5 hours with an overall nulling fraction of 31$\pm$2\%. The pulsar shows two distinct phases of emission. It is usually in an active phase, characterized by pulsations intersp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.04455v1-abstract-full').style.display = 'inline'; document.getElementById('1712.04455v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.04455v1-abstract-full" style="display: none;"> Single pulse observations, characterizing in detail, the nulling behaviour of PSR B1706$-$16 are being reported for the first time in this paper. Our regular long duration monitoring of this pulsar reveals long nulls of 2 to 5 hours with an overall nulling fraction of 31$\pm$2\%. The pulsar shows two distinct phases of emission. It is usually in an active phase, characterized by pulsations interspersed with shorter nulls, with a nulling fraction of about 15 \%, but it also rarely switches to an inactive phase, consisting of long nulls. The nulls in this pulsar are concurrent between 326.5 and 610 MHz. Profile mode changes accompanied by changes in fluctuation properties are seen in this pulsar, which switches from mode A before a null to mode B after the null. The distribution of null durations in this pulsar is bimodal. With its occasional long nulls, PSR B1706$-$16 joins the small group of intermediate nullers, which lie between the classical nullers and the intermittent pulsars. Similar to other intermediate nullers, PSR B1706$-$16 shows high timing noise, which could be due to its rare long nulls if one assumes that the slowdown rate during such nulls is different from that during the bursts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.04455v1-abstract-full').style.display = 'none'; document.getElementById('1712.04455v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.08613">arXiv:1706.08613</a> <span> [<a href="https://arxiv.org/pdf/1706.08613">pdf</a>, <a href="https://arxiv.org/ps/1706.08613">ps</a>, <a href="https://arxiv.org/format/1706.08613">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stx1615">10.1093/mnras/stx1615 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Detection of radio emission from the gamma-ray pulsar J1732-3131 at 327 MHz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A+K">Arun K. Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+S">Subhashis Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kerr%2C+M">Matthew Kerr</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1706.08613v1-abstract-short" style="display: inline;"> Although originally discovered as a radio-quiet gamma-ray pulsar, J1732-3131 has exhibited intriguing detections at decameter wavelengths. We report an extensive follow-up of the pulsar at 327 MHz with the Ooty radio telescope. Using the previously observed radio characteristics, and with an effective integration time of 60 hrs, we present a detection of the pulsar at a confidence level of 99.82%.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.08613v1-abstract-full').style.display = 'inline'; document.getElementById('1706.08613v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.08613v1-abstract-full" style="display: none;"> Although originally discovered as a radio-quiet gamma-ray pulsar, J1732-3131 has exhibited intriguing detections at decameter wavelengths. We report an extensive follow-up of the pulsar at 327 MHz with the Ooty radio telescope. Using the previously observed radio characteristics, and with an effective integration time of 60 hrs, we present a detection of the pulsar at a confidence level of 99.82%. The 327 MHz mean flux density is estimated to be 0.5-0.8 mJy, which establishes the pulsar to be a steep spectrum source and one of the least-luminous pulsars known to date. We also phase-aligned the radio and gamma-ray profiles of the pulsar, and measured the phase-offset between the main peaks in the two profiles to be 0.24$\pm$0.06. We discuss the observed phase-offset in the context of various trends exhibited by the radio-loud gamma-ray pulsar population, and suggest that the gamma-ray emission from J1732-3131 is best explained by outer magnetosphere models. Details of our analysis leading to the pulsar detection, and measurements of various parameters and their implications relevant to the pulsar's emission mechanism are presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.08613v1-abstract-full').style.display = 'none'; document.getElementById('1706.08613v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures; Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.05799">arXiv:1706.05799</a> <span> [<a href="https://arxiv.org/pdf/1706.05799">pdf</a>, <a href="https://arxiv.org/ps/1706.05799">ps</a>, <a href="https://arxiv.org/format/1706.05799">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aa7af2">10.3847/1538-4357/aa7af2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-frequency scatter broadening evolution of pulsars - I </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1706.05799v1-abstract-short" style="display: inline;"> We present multi-wavelength scatter broadening observations of 47 pulsars, made with the Giant Metre-wave Radio Telescope (GMRT), Ooty Radio Telescope (ORT) and Long Wavelength Array (LWA). The GMRT observations have been made in the phased array mode at 148, 234, and 610 MHz and the ORT observations at 327 MHz. The LWA data sets have been obtained from the LWA pulsar data archive. The broadening… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.05799v1-abstract-full').style.display = 'inline'; document.getElementById('1706.05799v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.05799v1-abstract-full" style="display: none;"> We present multi-wavelength scatter broadening observations of 47 pulsars, made with the Giant Metre-wave Radio Telescope (GMRT), Ooty Radio Telescope (ORT) and Long Wavelength Array (LWA). The GMRT observations have been made in the phased array mode at 148, 234, and 610 MHz and the ORT observations at 327 MHz. The LWA data sets have been obtained from the LWA pulsar data archive. The broadening of each pulsar as a function of observing frequency provides the frequency scaling index, $伪$. The estimations of $伪$ have been obtained for 39 pulsars, which include entirely new estimates for 31 pulsars. This study increases the total sample of pulsars available with $伪$ estimates by $\sim$50\%. The overall distribution of $伪$ with the dispersion measure (DM) of pulsar shows interesting variations, which are consistent with the earlier studies. However, for a given value of DM a range of $伪$ values are observed, indicating the characteristic turbulence along each line of sight. For each pulsar, the estimated level of turbulence, $C^{2}_{n_e}$, has also been compared with $伪$ and DM. Additionally, we compare the distribution of $伪$ with the theoretically predicated model to infer the general characteristics of the ionized interstellar medium (ISM). Nearly 65\% of the pulsars show a flatter index (i.e., $伪< 4.4$) than that is expected from the Kolmogorov turbulence model. Moreover, the group of pulsars having flatter index is typically associated with an enhanced value of $C^{2}_{n_e}$ than those with steeper index. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.05799v1-abstract-full').style.display = 'none'; document.getElementById('1706.05799v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 4 figures, 3 tables. Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1704.05048">arXiv:1704.05048</a> <span> [<a href="https://arxiv.org/pdf/1704.05048">pdf</a>, <a href="https://arxiv.org/format/1704.05048">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201629937">10.1051/0004-6361/201629937 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simultaneous multi-frequency single pulse observations of pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A Krishnakumar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1704.05048v1-abstract-short" style="display: inline;"> We performed simultaneous observations at 326.5 MHz with the Ooty Radio Telescope and at 326, 610 and 1308 MHz with the Giant Meterwave Radio Telescope for a sample of 12 pulsars, where frequency dependent single pulse behaviour was reported. The single pulse sequences were analysed with fluctuation analysis, sensitive to both the average fluctuation properties (using longitude resolved fluctuatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.05048v1-abstract-full').style.display = 'inline'; document.getElementById('1704.05048v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1704.05048v1-abstract-full" style="display: none;"> We performed simultaneous observations at 326.5 MHz with the Ooty Radio Telescope and at 326, 610 and 1308 MHz with the Giant Meterwave Radio Telescope for a sample of 12 pulsars, where frequency dependent single pulse behaviour was reported. The single pulse sequences were analysed with fluctuation analysis, sensitive to both the average fluctuation properties (using longitude resolved fluctuation spectrum and two-dimensional fluctuation spectrum) as well as temporal changes in these (using sliding two-dimensional fluctuation spectrum ) to establish concurrent changes in subpulse drifting over the multiple frequencies employed. We report subpulse drifting in PSR J0934$-$5249 for the first time. We also report pulse nulling measurements in PSRs J0934$-$5249, B1508+55, J1822$-$2256, B1845$-$19 and J1901$-$0906 for the first time. Our measurements of subpulse drifting and pulse nulling for the rest of the pulsars are consistent with previously reported values. Contrary to previous belief, we find no evidence for a frequency dependent drift pattern in PSR B2016+28 implied by non-simultaneous observations by Oster et al. (1977). In PSRs B1237+25, J1822$-$2256, J1901$-$0906 and B2045$-$16, our longer and more sensitive observations reveal multiple drift rates with distinct P3. We increase the sample of pulsars showing concurrent nulling across multiple frequencies by more than 100 percent, adding 4 more pulsars to this sample. Our results confirm and further strengthen the understanding that the subpulse drifting and pulse nulling are broadband consistent with previous studies (Gajjar et al. 2014a; Rankin 1986; Weltevrede et al. 2007) and are closely tied to physics of polar gap. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1704.05048v1-abstract-full').style.display = 'none'; document.getElementById('1704.05048v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 44 figures, Single pulse studies of pulsars, accepted by A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 604, A45 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.02587">arXiv:1702.02587</a> <span> [<a href="https://arxiv.org/pdf/1702.02587">pdf</a>, <a href="https://arxiv.org/format/1702.02587">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201630093">10.1051/0004-6361/201630093 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio and X-ray properties of the source G29.37+0.1 linked to HESS J1844-030 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Castelletti%2C+G">G. Castelletti</a>, <a href="/search/astro-ph?searchtype=author&query=Supan%2C+L">L. Supan</a>, <a href="/search/astro-ph?searchtype=author&query=Petriella%2C+A">A. Petriella</a>, <a href="/search/astro-ph?searchtype=author&query=Giacani%2C+E">E. Giacani</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1702.02587v1-abstract-short" style="display: inline;"> Using observations carried out with the GMRT, we performed high-quality full-synthesis imaging at 610 MHz of the source G29.37+0.1, which is an as-yet-unclassified object linked to the TeV source HESS J1844-030. These data, combined with observations at 1400 MHz from MAGPIS were used to investigate the properties of its radio emission. Additionally, we reprocessed XMM-Newton and Chandra archival d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.02587v1-abstract-full').style.display = 'inline'; document.getElementById('1702.02587v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.02587v1-abstract-full" style="display: none;"> Using observations carried out with the GMRT, we performed high-quality full-synthesis imaging at 610 MHz of the source G29.37+0.1, which is an as-yet-unclassified object linked to the TeV source HESS J1844-030. These data, combined with observations at 1400 MHz from MAGPIS were used to investigate the properties of its radio emission. Additionally, we reprocessed XMM-Newton and Chandra archival data. G29.37+0.1 mainly consists of a bright twisted structure, named the S-shaped feature. The high sensitivity of the new GMRT observations allowed the identification of potential lobes, jets, and a nuclear central region in the S-shaped morphology of G29.37+0.1. We also highlight the detection of diffuse and low surface brightness emission enveloping the brightest emitting regions. The brightest emission in G29.37+0.1 has a radio synchrotron spectral index 0.59+/-0.09. Variations in the spectral behavior are observed across the whole radio source with the flattest spectral features in the central nuclear and jets components (alpha~0.3). These results lead us to conclude that the brightest radio emission from G29.37+0.1 likely represents a newly recognized radio galaxy. The identification of optical and infrared counterparts to the emission from the core of G29.37+0.1 strengthens our interpretation of an extragalactic origin of the radio emission. Our spectral analysis demonstrated that a non-thermal origin for the X-ray emission compatible with a pulsar wind nebula is quite possible. The analysis of the spatial distribution of the CO gas revealed the presence of a complex of molecular clouds located in projection adjacent to the radio halo emission and probably interacting with it. We propose that the faint halo represents a composite supernova remnant with a pulsar powered component given by the diffuse X-ray emission superimposed along the line of sight to the radio galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.02587v1-abstract-full').style.display = 'none'; document.getElementById('1702.02587v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 figures, accepted to be published in Astronomy and Astrophysics Main Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 602, A31 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1610.08175">arXiv:1610.08175</a> <span> [<a href="https://arxiv.org/pdf/1610.08175">pdf</a>, <a href="https://arxiv.org/ps/1610.08175">ps</a>, <a href="https://arxiv.org/format/1610.08175">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="General Relativity and Quantum Cosmology">gr-qc</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s12036-016-9409-6">10.1007/s12036-016-9409-6 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Neutron Star Physics in the Square Kilometer Array Era : An Indian Perspective </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Konar%2C+S">Sushan Konar</a>, <a href="/search/astro-ph?searchtype=author&query=Bagchi%2C+M">Manjari Bagchi</a>, <a href="/search/astro-ph?searchtype=author&query=Bandyopadhyay%2C+D">Debades Bandyopadhyay</a>, <a href="/search/astro-ph?searchtype=author&query=Banik%2C+S">Sarmistha Banik</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharya%2C+D">Dipankar Bhattacharya</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+S">Sudip Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Gangadhara%2C+R+T">R. T. Gangadhara</a>, <a href="/search/astro-ph?searchtype=author&query=Gopakumar%2C+A">A. Gopakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Yashwant Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Maitra%2C+C">Chandreyee Maitra</a>, <a href="/search/astro-ph?searchtype=author&query=Mukherjee%2C+D">Dipanjan Mukherjee</a>, <a href="/search/astro-ph?searchtype=author&query=Pai%2C+A">Archana Pai</a>, <a href="/search/astro-ph?searchtype=author&query=Paul%2C+B">Biswajit Paul</a>, <a href="/search/astro-ph?searchtype=author&query=Ray%2C+A+K">Alak K. Ray</a>, <a href="/search/astro-ph?searchtype=author&query=Sutaria%2C+F+K">Firoza K. Sutaria</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1610.08175v1-abstract-short" style="display: inline;"> It is an exceptionally opportune time for Astrophysics when a number of next-generation mega-instruments are poised to observe the universe across the entire electromagnetic spectrum with unprecedented data quality. The Square Kilometre Array (SKA) is undoubtedly one of the major components of this scenario. In particular, the SKA is expected to discover tens of thousands of new neutron stars givi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.08175v1-abstract-full').style.display = 'inline'; document.getElementById('1610.08175v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.08175v1-abstract-full" style="display: none;"> It is an exceptionally opportune time for Astrophysics when a number of next-generation mega-instruments are poised to observe the universe across the entire electromagnetic spectrum with unprecedented data quality. The Square Kilometre Array (SKA) is undoubtedly one of the major components of this scenario. In particular, the SKA is expected to discover tens of thousands of new neutron stars giving a major fillip to a wide range of scientific investigations. India has a sizeable community of scientists working on different aspects of neutron star physics with immediate access to both the uGMRT (an SKA pathfinder) and the recently launched X-ray observatory Astrosat. The current interests of the community largely centre around studies of - a) the generation of neutron stars and the SNe connection}, b) the neutron star population and evolutionary pathways}, c) the evolution of neutron stars in binaries and the magnetic fields}, d) the neutron star equation of state}, e) the radio pulsar emission mechanism}, and, f) the radio pulsars as probes of gravitational physics}. Most of these studies are the main goals of the SKA first phase, which is likely to be operational in the next four years. This article summarises the science goals of the Indian neutron star community in the SKA era, with significant focus on coordinated efforts among the SKA and other existing/upcoming instruments. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.08175v1-abstract-full').style.display = 'none'; document.getElementById('1610.08175v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">To appear in Journal of Astrophysics and Astronomy (JOAA) special issue on "Science with the SKA: an Indian perspective"</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Astrophys. Astr. 37 36 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.04008">arXiv:1609.04008</a> <span> [<a href="https://arxiv.org/pdf/1609.04008">pdf</a>, <a href="https://arxiv.org/ps/1609.04008">ps</a>, <a href="https://arxiv.org/format/1609.04008">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stw2353">10.1093/mnras/stw2353 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> PSR B0329+54: Substructure in the scatter-broadened image discovered with RadioAstron on baselines up to 330,000 km </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Popov%2C+M+V">M. V. Popov</a>, <a href="/search/astro-ph?searchtype=author&query=Bartel%2C+N">N. Bartel</a>, <a href="/search/astro-ph?searchtype=author&query=Gwinn%2C+C+R">C. R. Gwinn</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+M+D">M. D. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Andrianov%2C+A">A. Andrianov</a>, <a href="/search/astro-ph?searchtype=author&query=Fadeev%2C+E">E. Fadeev</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kardashev%2C+N+S">N. S. Kardashev</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kovalev%2C+Y+Y">Y. Y. Kovalev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnitskiy%2C+A">A. Rudnitskiy</a>, <a href="/search/astro-ph?searchtype=author&query=Shishov%2C+V+I">V. I. Shishov</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnova%2C+T+V">T. V. Smirnova</a>, <a href="/search/astro-ph?searchtype=author&query=Soglasnov%2C+V+A">V. A. Soglasnov</a>, <a href="/search/astro-ph?searchtype=author&query=Zensus%2C+J+A">J. A. Zensus</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1609.04008v1-abstract-short" style="display: inline;"> We have resolved the scatter-broadened image of PSR B0329+54 and detected substructure within it. These results are not influenced by any extended structure of a source but instead are directly attributed to the interstellar medium. We obtained these results at 324 MHz with the ground-space interferometer RadioAstron which included the space radio telescope (SRT), ground-based Westerbork Synthesis… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.04008v1-abstract-full').style.display = 'inline'; document.getElementById('1609.04008v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.04008v1-abstract-full" style="display: none;"> We have resolved the scatter-broadened image of PSR B0329+54 and detected substructure within it. These results are not influenced by any extended structure of a source but instead are directly attributed to the interstellar medium. We obtained these results at 324 MHz with the ground-space interferometer RadioAstron which included the space radio telescope (SRT), ground-based Westerbork Synthesis Radio Telescope and 64-m Kalyazin Radio Telescope on baseline projections up to 330,000 km in 2013 November 22 and 2014 January 1 to 2. At short 15,000 to 35,000 km ground-space baseline projections the visibility amplitude decreases with baseline length providing a direct measurement of the size of the scattering disk of 4.8$\pm$0.8 mas. At longer baselines no visibility detections from the scattering disk would be expected. However, significant detections were obtained with visibility amplitudes of 3 to 5% of the maximum scattered around a mean and approximately constant up to 330,000 km. These visibilities reflect substructure from scattering in the interstellar medium and offer a new probe of ionized interstellar material. The size of the diffraction spot near Earth is 17,000$\pm$3,000 km. With the assumption of turbulent irregularities in the plasma of the interstellar medium, we estimate that the effective scattering screen is located 0.6$\pm$0.1 of the distance from Earth toward the pulsar. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.04008v1-abstract-full').style.display = 'none'; document.getElementById('1609.04008v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 September, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 4 figures, 2 tables; accepted by MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.08276">arXiv:1605.08276</a> <span> [<a href="https://arxiv.org/pdf/1605.08276">pdf</a>, <a href="https://arxiv.org/ps/1605.08276">ps</a>, <a href="https://arxiv.org/format/1605.08276">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-637X/826/2/184">10.3847/0004-637X/826/2/184 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Radio Pulsation Search and Imaging Study of SGR J1935+2154 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M">Mayuresh Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1605.08276v1-abstract-short" style="display: inline;"> We present the results obtained from imaging observations, and search for radio pulsations towards the magnetar SGR J1935+2154 made using the Giant Metrewave Radio Telescope, and the Ooty Radio Telescope. We present the high resolution radio image of the supernova remnant (SNR) G57.2+0.8, which is positionally associated with SGR J1935+2154. We did not detect significant periodic radio pulsations… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.08276v1-abstract-full').style.display = 'inline'; document.getElementById('1605.08276v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.08276v1-abstract-full" style="display: none;"> We present the results obtained from imaging observations, and search for radio pulsations towards the magnetar SGR J1935+2154 made using the Giant Metrewave Radio Telescope, and the Ooty Radio Telescope. We present the high resolution radio image of the supernova remnant (SNR) G57.2+0.8, which is positionally associated with SGR J1935+2154. We did not detect significant periodic radio pulsations from the magnetar, with 8$蟽$ upper limits on its flux density of 0.4, and 0.2 mJy at 326.5, and 610 MHz, respectively, for an assumed duty cycle of 10\%. The corresponding 6$蟽$ upper limits at the two frequencies for any burst emission with an assumed width of 10 ms are 0.5 Jy, and 63 mJy, respectively. No continuum radio point source was detected at the position of SGR J1935+2154 with a 3$蟽$ upper limit of 1.2 mJy. We also did not detect significant diffuse radio emission in a radius of 70 arc seconds in coincidence with the diffuse X-ray emission reported recently, with a 3$蟽$ upper limit of 4.5 mJy. Using the archival HI spectra, we estimate the distance of SNR G57.2+0.8 to be 11.7 $\pm$ 2.8 kpc. Based on measured HI column density (N$_H$) along this line of sight, we argue that the magnetar could be physically associated with SNR G57.2+0.8. Based on present data, we can not rule out either a pulsar wind nebula or a dust scattering halo origin for the diffuse X-ray emission seen around the magnetar. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.08276v1-abstract-full').style.display = 'none'; document.getElementById('1605.08276v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2016. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 4 figures. Accepted for publication in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, July 2016, Volume 826, Number 2 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1503.01405">arXiv:1503.01405</a> <span> [<a href="https://arxiv.org/pdf/1503.01405">pdf</a>, <a href="https://arxiv.org/ps/1503.01405">ps</a>, <a href="https://arxiv.org/format/1503.01405">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s10686-015-9450-5">10.1007/s10686-015-9450-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> PONDER - A Real time software backend for pulsar and IPS observations at the Ooty Radio Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K Manoharan</a>, <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A Krishnakumar</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1503.01405v1-abstract-short" style="display: inline;"> This paper describes a new real-time versatile backend, the Pulsar Ooty Radio Telescope New Digital Efficient Receiver (PONDER), which has been designed to operate along with the legacy analog system of the Ooty Radio Telescope (ORT). PONDER makes use of the current state of the art computing hardware, a Graphical Processing Unit (GPU) and sufficiently large disk storage to support high time resol… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.01405v1-abstract-full').style.display = 'inline'; document.getElementById('1503.01405v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1503.01405v1-abstract-full" style="display: none;"> This paper describes a new real-time versatile backend, the Pulsar Ooty Radio Telescope New Digital Efficient Receiver (PONDER), which has been designed to operate along with the legacy analog system of the Ooty Radio Telescope (ORT). PONDER makes use of the current state of the art computing hardware, a Graphical Processing Unit (GPU) and sufficiently large disk storage to support high time resolution real-time data of pulsar observations, obtained by coherent dedispersion over a bandpass of 16 MHz. Four different modes for pulsar observations are implemented in PONDER to provide standard reduced data products, such as time-stamped integrated profiles and dedispersed time series, allowing faster avenues to scientific results for a variety of pulsar studies. Additionally, PONDER also supports general modes of interplanetary scintillation (IPS) measurements and very long baseline interferometry data recording. The IPS mode yields a single polarisation correlated time series of solar wind scintillation over a bandwidth of about four times larger (16 MHz) than that of the legacy system as well as its fluctuation spectrum with high temporal and frequency resolutions. The key point is that all the above modes operate in real time. This paper presents the design aspects of PONDER and outlines the design methodology for future similar backends. It also explains the principal operations of PONDER, illustrates its capabilities for a variety of pulsar and IPS observations and demonstrates its usefulness for a variety of astrophysical studies using the high sensitivity of the ORT. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1503.01405v1-abstract-full').style.display = 'none'; document.getElementById('1503.01405v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 March, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">25 pages, 14 figures, Accepted by Experimental Astronomy</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1502.01224">arXiv:1502.01224</a> <span> [<a href="https://arxiv.org/pdf/1502.01224">pdf</a>, <a href="https://arxiv.org/ps/1502.01224">ps</a>, <a href="https://arxiv.org/format/1502.01224">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201425284">10.1051/0004-6361/201425284 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A complete radio study of SNR G15.4+0.1 from new GMRT observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Supan%2C+L">L. Supan</a>, <a href="/search/astro-ph?searchtype=author&query=Castelletti%2C+G">G. Castelletti</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">M. P. Surnis</a>, <a href="/search/astro-ph?searchtype=author&query=Supanitsky%2C+D">D. Supanitsky</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1502.01224v1-abstract-short" style="display: inline;"> The supernova remnant G15.4+0.1 is considered to be the possible counterpart of the gamma-ray source HESSJ1818-154. With the goal of getting a complete view of this remnant and understanding the nature of the gamma-ray flux, we conducted a detailed radio study that includes the search for pulsations and a model of the broadband emission for the G15.4+0.1/HESSJ1818-154 system. Low-frequency imaging… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.01224v1-abstract-full').style.display = 'inline'; document.getElementById('1502.01224v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.01224v1-abstract-full" style="display: none;"> The supernova remnant G15.4+0.1 is considered to be the possible counterpart of the gamma-ray source HESSJ1818-154. With the goal of getting a complete view of this remnant and understanding the nature of the gamma-ray flux, we conducted a detailed radio study that includes the search for pulsations and a model of the broadband emission for the G15.4+0.1/HESSJ1818-154 system. Low-frequency imaging at 624 MHz and pulsar observations at 624 and 1404 MHz towards G15.4+0.1 were carried out with the Giant Metrewave Radio Telescope (GMRT). We correlated the new radio data with observations of the source at X-ray and infrared wavelengths from XMM-Newton and Herschel observatories, respectively. To characterize the neutral hydrogen medium (HI) towards G15.4+0.1, we used data from the Southern Galactic Plane Survey. We modelled the spectral energy distribution using both hadronic and leptonic scenarios. From the combination of the new GMRT observations with existing data, we derived a continuum spectral index alpha=-0.62+-0.03 for the whole remnant. The local synchrotron spectra of G15.4+0.1, calculated from the combination of the GMRT data with 330 MHz observations from the VLA, tends to be flatter in the central part of the remnant, accompanying the region where the blast wave is impinging molecular gas. No spectral index trace was found indicating the radio counterpart to the pulsar wind nebula proposed from X-ray observations. In addition, the search for radio pulsations yielded negative results. Emission at far-infrared wavelengths is observed in the region where the SNR shock is interacting with dense molecular clumps. We also identified HI features forming a shell that wraps most of the outer border of G15.4+0.1. Characteristic parameters were estimated for the shocked HI gas. We found that either a purely hadronic or leptonic model is compatible with the broadband emission known so far. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.01224v1-abstract-full').style.display = 'none'; document.getElementById('1502.01224v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 February, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 9 figures, accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 576, A81 (2015) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.05401">arXiv:1501.05401</a> <span> [<a href="https://arxiv.org/pdf/1501.05401">pdf</a>, <a href="https://arxiv.org/ps/1501.05401">ps</a>, <a href="https://arxiv.org/format/1501.05401">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/804/1/23">10.1088/0004-637X/804/1/23 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Scatter broadening measurements of 124 pulsars at 327 MHz </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Krishnakumar%2C+M+A">M. A. Krishnakumar</a>, <a href="/search/astro-ph?searchtype=author&query=Mitra%2C+D">Dipanjan Mitra</a>, <a href="/search/astro-ph?searchtype=author&query=Naidu%2C+A">Arun Naidu</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Manoharan%2C+P+K">P. K. Manoharan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1501.05401v1-abstract-short" style="display: inline;"> We present the measurements of scatter broadening time-scales ($蟿_{sc}$) for 124 pulsars at 327 MHz, using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37 $-$ 503 pc cm$^{-3}$ and declination ($未$) range of $-$57$^{\circ} < 未< 60^{\circ}$. New $蟿_{sc}$ estimates for 58 pulsars are presented, increasing the sample of all such measurements by about 40… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.05401v1-abstract-full').style.display = 'inline'; document.getElementById('1501.05401v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.05401v1-abstract-full" style="display: none;"> We present the measurements of scatter broadening time-scales ($蟿_{sc}$) for 124 pulsars at 327 MHz, using the upgraded Ooty Radio Telescope (ORT). These pulsars lie in the dispersion measure range of 37 $-$ 503 pc cm$^{-3}$ and declination ($未$) range of $-$57$^{\circ} < 未< 60^{\circ}$. New $蟿_{sc}$ estimates for 58 pulsars are presented, increasing the sample of all such measurements by about 40% at 327 MHz. Using all available $蟿_{sc}$ measurements in the literature, we investigate the dependence of $蟿_{sc}$ on dispersion measure. Our measurements, together with previously reported values for $蟿_{sc}$, affirm that the ionized interstellar medium upto 3 kpc is consistent with Kolmogorov spectrum, while it deviates significantly beyond this distance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.05401v1-abstract-full').style.display = 'none'; document.getElementById('1501.05401v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 4 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1501.04449">arXiv:1501.04449</a> <span> [<a href="https://arxiv.org/pdf/1501.04449">pdf</a>, <a href="https://arxiv.org/format/1501.04449">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/0004-637X/822/2/96">10.3847/0004-637X/822/2/96 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> PSR B0329+54: Statistics of Substructure Discovered within the Scattering Disk on RadioAstron Baselines of up to 235,000 km </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gwinn%2C+C+R">C. R. Gwinn</a>, <a href="/search/astro-ph?searchtype=author&query=Popov%2C+M+V">M. V. Popov</a>, <a href="/search/astro-ph?searchtype=author&query=Bartel%2C+N">N. Bartel</a>, <a href="/search/astro-ph?searchtype=author&query=Andrianov%2C+A+S">A. S. Andrianov</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+M+D">M. D. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kardashev%2C+N+S">N. S. Kardashev</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kovalev%2C+Y+Y">Y. Y. Kovalev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Rudnitskii%2C+A+G">A. G. Rudnitskii</a>, <a href="/search/astro-ph?searchtype=author&query=Safutdinov%2C+E+R">E. R. Safutdinov</a>, <a href="/search/astro-ph?searchtype=author&query=Shishov%2C+V+I">V. I. Shishov</a>, <a href="/search/astro-ph?searchtype=author&query=Smirnova%2C+T+V">T. V. Smirnova</a>, <a href="/search/astro-ph?searchtype=author&query=Soglasnov%2C+V+A">V. A. Soglasnov</a>, <a href="/search/astro-ph?searchtype=author&query=Steinmassl%2C+S+F">S. F. Steinmassl</a>, <a href="/search/astro-ph?searchtype=author&query=Zensus%2C+J+A">J. A. Zensus</a>, <a href="/search/astro-ph?searchtype=author&query=Zhuravlev%2C+V+I">V. I. Zhuravlev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1501.04449v3-abstract-short" style="display: inline;"> We discovered fine-scale structure within the scattering disk of PSR B0329+54 in observations with the RadioAstron ground-space radio interferometer. Here, we describe this phenomenon, characterize it with averages and correlation functions, and interpret it as the result of decorrelation of the impulse-response function of interstellar scattering between the widely-separated antennas. This instru… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.04449v3-abstract-full').style.display = 'inline'; document.getElementById('1501.04449v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1501.04449v3-abstract-full" style="display: none;"> We discovered fine-scale structure within the scattering disk of PSR B0329+54 in observations with the RadioAstron ground-space radio interferometer. Here, we describe this phenomenon, characterize it with averages and correlation functions, and interpret it as the result of decorrelation of the impulse-response function of interstellar scattering between the widely-separated antennas. This instrument included the 10-m Space Radio Telescope, the 110-m Green Bank Telescope, the 14x25-m Westerbork Synthesis Radio Telescope, and the 64-m Kalyazin Radio Telescope. The observations were performed at 324 MHz, on baselines of up to 235,000 km in November 2012 and January 2014. In the delay domain, on long baselines the interferometric visibility consists of many discrete spikes within a limited range of delays. On short baselines it consists of a sharp spike surrounded by lower spikes. The average envelope of correlations of the visibility function show two exponential scales, with characteristic delays of $蟿_1=4.1\pm 0.3\ 渭{\rm s}$ and $蟿_2=23\pm 3\ 渭{\rm s}$, indicating the presence of two scales of scattering in the interstellar medium. These two scales are present in the pulse-broadening function. The longer scale contains 0.38 times the scattered power of the shorter one. We suggest that the longer tail arises from highly-scattered paths, possibly from anisotropic scattering or from substructure at large angles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1501.04449v3-abstract-full').style.display = 'none'; document.getElementById('1501.04449v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 January, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2015. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 6 figures, 3 tables; accepted by Astrophysical journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophysical journal 822 (2016) 96 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1409.5589">arXiv:1409.5589</a> <span> [<a href="https://arxiv.org/pdf/1409.5589">pdf</a>, <a href="https://arxiv.org/ps/1409.5589">ps</a>, <a href="https://arxiv.org/format/1409.5589">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/797/1/18">10.1088/0004-637X/797/1/18 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Frequency independent quenching of pulsed emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gajjar%2C+V">Vishal Gajjar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">Michael Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">Ramesh Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">Roy Smits</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1409.5589v2-abstract-short" style="display: inline;"> Simultaneous observations at four different frequencies viz. 313, 607, 1380 and 4850 MHz, for three pulsars, PSRs B0031-07, B0809+74 and B2319+60, are reported in this paper. Identified null and burst pulses are highly concurrent across more than decade of frequency. Small fraction of non-concurrent pulses (less than or equal to 3%) are observed, most of which occur at the transition instances. We… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.5589v2-abstract-full').style.display = 'inline'; document.getElementById('1409.5589v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1409.5589v2-abstract-full" style="display: none;"> Simultaneous observations at four different frequencies viz. 313, 607, 1380 and 4850 MHz, for three pulsars, PSRs B0031-07, B0809+74 and B2319+60, are reported in this paper. Identified null and burst pulses are highly concurrent across more than decade of frequency. Small fraction of non-concurrent pulses (less than or equal to 3%) are observed, most of which occur at the transition instances. We report, with very high significance for the first time, full broadband nature of the nulling phenomenon in these three pulsars. These results suggest that nulling invokes changes on the global magnetospheric scale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1409.5589v2-abstract-full').style.display = 'none'; document.getElementById('1409.5589v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 September, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 Pages, 2 Figures, 3 Tables, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1402.6346">arXiv:1402.6346</a> <span> [<a href="https://arxiv.org/pdf/1402.6346">pdf</a>, <a href="https://arxiv.org/ps/1402.6346">ps</a>, <a href="https://arxiv.org/format/1402.6346">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/0004-637X/786/2/115">10.1088/0004-637X/786/2/115 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> RadioAstron Studies of the Nearby, Turbulent Interstellar Plasma With the Longest Space-Ground Interferometer Baseline </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smirnova%2C+T+V">T. V. Smirnova</a>, <a href="/search/astro-ph?searchtype=author&query=Shishov%2C+V+I">V. I. Shishov</a>, <a href="/search/astro-ph?searchtype=author&query=Popov%2C+M+V">M. V. Popov</a>, <a href="/search/astro-ph?searchtype=author&query=Gwinn%2C+C+R">C. R. Gwinn</a>, <a href="/search/astro-ph?searchtype=author&query=Anderson%2C+J+M">J. M. Anderson</a>, <a href="/search/astro-ph?searchtype=author&query=Andrianov%2C+A+S">A. S. Andrianov</a>, <a href="/search/astro-ph?searchtype=author&query=Bartel%2C+N">N. Bartel</a>, <a href="/search/astro-ph?searchtype=author&query=Deller%2C+A">A. Deller</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+M+D">M. D. Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kardashev%2C+N+S">N. S. Kardashev</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kovalev%2C+Y+Y">Y. Y. Kovalev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Soglasnov%2C+V+A">V. A. Soglasnov</a>, <a href="/search/astro-ph?searchtype=author&query=Zensus%2C+J+A">J. A. Zensus</a>, <a href="/search/astro-ph?searchtype=author&query=Zhuravlev%2C+V+I">V. I. Zhuravlev</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1402.6346v1-abstract-short" style="display: inline;"> RadioAstron space-ground VLBI observations of the pulsar B0950+08, conducted with the 10-m space radio telescope in conjunction with the Arecibo 300-m telescope and Westerbork Synthesis Radio Telescope at a frequency of 324 MHz, were analyzed in order to investigate plasma inhomogeneities in the direction of this nearby pulsar. The observations were conducted at a spacecraft distance of 330,000 km… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6346v1-abstract-full').style.display = 'inline'; document.getElementById('1402.6346v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1402.6346v1-abstract-full" style="display: none;"> RadioAstron space-ground VLBI observations of the pulsar B0950+08, conducted with the 10-m space radio telescope in conjunction with the Arecibo 300-m telescope and Westerbork Synthesis Radio Telescope at a frequency of 324 MHz, were analyzed in order to investigate plasma inhomogeneities in the direction of this nearby pulsar. The observations were conducted at a spacecraft distance of 330,000 km, resulting in a projected baseline of 220,000 km, providing the greatest angular resolution ever achieved at meter wavelengths. Our analysis is based on fundamental behavior of structure and coherence functions. We find that the pulsar shows scintillation on two frequency scales, both much less than the observing frequency; but modulation is less than 100%. We infer that the scattering is weak, but a refracting wedge disperses the scintillation pattern. The refraction angle of this "cosmic prism" is measured as theta_0=1.1 - 4.4 mas, with the refraction direction being approximately perpendicular to the observer velocity. We show that the observed parameters of scintillation effects indicate that two plasma layers lie along the line of sight to the pulsar, at distances of 4.4 - 16.4 pc and 26 - 170 pc, and traveling in different directions relative to the line of sight. Spectra of turbulence for the two layers are found to follow a power law with the indices gamma_1 = gamma_2 = 3.00 +/- 0.08, significantly different from the index expected for a Kolmogorov spectrum of turbulence, gamma=11/3. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1402.6346v1-abstract-full').style.display = 'none'; document.getElementById('1402.6346v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 February, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2014. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">52 manuscript pages, 10 figures. Submitted to ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrophysical Journal 786 (2014) 115 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1312.2729">arXiv:1312.2729</a> <span> [<a href="https://arxiv.org/pdf/1312.2729">pdf</a>, <a href="https://arxiv.org/ps/1312.2729">ps</a>, <a href="https://arxiv.org/format/1312.2729">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnras/stt2389">10.1093/mnras/stt2389 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the long nulls of PSRs J1738-2330 and J1752+2359 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Gajjar%2C+V">Vishal Gajjar</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">Bhal Chandra Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Wright%2C+G">Geoffrey Wright</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1312.2729v1-abstract-short" style="display: inline;"> This paper compares and contrasts the emission of two high nulling fraction pulsars, PSRs J1738-2330 and J1752+2359. In both pulsars the emission bursts appear in a quasi-periodic fashion with typical separations of several hundred pulses, and in J1738-2330 there is evidence of two underlying periodicities with memory persisting for at least 11 bursts. By contrast, in J1752+2359 the pattern cohere… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.2729v1-abstract-full').style.display = 'inline'; document.getElementById('1312.2729v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1312.2729v1-abstract-full" style="display: none;"> This paper compares and contrasts the emission of two high nulling fraction pulsars, PSRs J1738-2330 and J1752+2359. In both pulsars the emission bursts appear in a quasi-periodic fashion with typical separations of several hundred pulses, and in J1738-2330 there is evidence of two underlying periodicities with memory persisting for at least 11 bursts. By contrast, in J1752+2359 the pattern coherence is rapidly lost and the burst/null lengths appear to be selected randomly from their respective quasi-normal distributions. The typical emission bursts of J1738-2330 exhibit a steady exponential decay of on-pulse energy accompanied by a flickering emission characterized by short frequent nulls towards their end. In the bursts of J1752+2359 the flickering is absent, the decay more pronounced and the energy released during each bright phase is approximately constant. Unlike J1738-2330, the average profiles for the first and the last pulses of J1752+2359 bursts differ slightly from the pulsar's overall profile, hinting at differences between the two pulsars in their transitions from null to burst state (and vice-versa). During its long null phases, J1752+2359 is found to emit random weak inter-burst pulses (IBPs) whose profile peak is somewhat offset with respect to the overall average profile. Such pulses have no equivalent in J1738-2330 or in any known pulsar hitherto. They may pervade the entire emission of this pulsar and have a separate physical origin to normal pulses. On the basis of our comparison we conclude that a pulsar's nulling fraction, even when high, remains a poor guide to its detailed subpulse behaviour, as previously found for pulsars with small nulling fractions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1312.2729v1-abstract-full').style.display = 'none'; document.getElementById('1312.2729v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 December, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 Pages, 15 Figures, Accepted for publication in MNRAS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1309.6026">arXiv:1309.6026</a> <span> [<a href="https://arxiv.org/pdf/1309.6026">pdf</a>, <a href="https://arxiv.org/ps/1309.6026">ps</a>, <a href="https://arxiv.org/format/1309.6026">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201322350">10.1051/0004-6361/201322350 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A hadronic scenario for HESS J1818-154 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Castelletti%2C+G">G. Castelletti</a>, <a href="/search/astro-ph?searchtype=author&query=Supan%2C+L">L. Supan</a>, <a href="/search/astro-ph?searchtype=author&query=Dubner%2C+G">G. Dubner</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Surnis%2C+M+P">M. P. Surnis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1309.6026v1-abstract-short" style="display: inline;"> Aims: G15.4+0.1 is a faint supernova remnant (SNR) that has recently been associated with the gamma-ray source HESS J1818-154. We investigate a hadronic scenario for the production of the gamma-ray emission. Methods: Molecular 13CO (J=1-0) taken from the Galactic Ring Survey (GRS) and neutral hydrogen (HI) data from the Southern Galactic Plane Survey (SGPS) have been used in combination with new 1… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.6026v1-abstract-full').style.display = 'inline'; document.getElementById('1309.6026v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1309.6026v1-abstract-full" style="display: none;"> Aims: G15.4+0.1 is a faint supernova remnant (SNR) that has recently been associated with the gamma-ray source HESS J1818-154. We investigate a hadronic scenario for the production of the gamma-ray emission. Methods: Molecular 13CO (J=1-0) taken from the Galactic Ring Survey (GRS) and neutral hydrogen (HI) data from the Southern Galactic Plane Survey (SGPS) have been used in combination with new 1420 MHz radio continuum observations carried out with the Giant Metrewave Radio Telescope (GMRT). Results: From the new observations and analysis of archival data we provided for the first time a reliable estimate for the distance to the SNR G15.4+0.1 and discovered molecular clouds located at the same distance. On the basis of HI absorption features, we estimate the distance to G15.4+0.1 in 4.8+/-1.0 kpc. The 13CO observations clearly show a molecular cloud about 5 arcmin in size with two bright clumps, labeled A and B, clump A positionally associated with the location of HESS J1818-154 and clump B in coincidence with the brightest northern border of the radio SNR shell. The HI absorption and the 13CO emission study indicates a possible interaction between the molecular material and the remnant. We estimate the masses and densities of the molecular gas as (1.2+/-0.5)X10^3 M_sun and (1.5+/-0.4)X10^3 cm^-3 for clump A and (3.0+/-0.7)X10^3 M_sun and (1.1+/-0.3)X10^3 cm^-3 for clump B. Calculations show that the average density of the molecular clump A is sufficient to produce the detected gamma-ray flux, thus favoring a hadronic origin for the high-energy emission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1309.6026v1-abstract-full').style.display = 'none'; document.getElementById('1309.6026v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 September, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to be published in Astronomy and Astrophysics Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&AL, 2013, vol. 557 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1304.4467">arXiv:1304.4467</a> <span> [<a href="https://arxiv.org/pdf/1304.4467">pdf</a>, <a href="https://arxiv.org/ps/1304.4467">ps</a>, <a href="https://arxiv.org/format/1304.4467">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1017/S1743921312024775">10.1017/S1743921312024775 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the Glitch Evolution of Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Urama%2C+J+O">J. O. Urama</a>, <a href="/search/astro-ph?searchtype=author&query=Joshi%2C+B+C">B. C. Joshi</a>, <a href="/search/astro-ph?searchtype=author&query=Chukwude%2C+A+E">A. E. Chukwude</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1304.4467v1-abstract-short" style="display: inline;"> Observations of pulsar glitches remain a powerful tool for studying the interior of neutron stars. Many of the observed glitch properties are shown to result from the evolution of glitches in the different manifestations of neutron stars. Specifically, the type of glitches associated with the Crab and Vela pulsars are explained by this model. We are, also, able to adequately account for the absenc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1304.4467v1-abstract-full').style.display = 'inline'; document.getElementById('1304.4467v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1304.4467v1-abstract-full" style="display: none;"> Observations of pulsar glitches remain a powerful tool for studying the interior of neutron stars. Many of the observed glitch properties are shown to result from the evolution of glitches in the different manifestations of neutron stars. Specifically, the type of glitches associated with the Crab and Vela pulsars are explained by this model. We are, also, able to adequately account for the absence, or very low rate, of glitches among the youngest and the very old pulsars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1304.4467v1-abstract-full').style.display = 'none'; document.getElementById('1304.4467v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 April, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2013. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Proceedings of IAUS 291 "Neutron Stars and Pulsars: Challenges and Opportunities after 80 years", J. van Leeuwen (ed.); 3 pages, 2 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Proceedings of the International Astronomical Union, Volume 291, pp. 533-535, 2013 </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Joshi%2C+B+C&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  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