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<button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <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/2208.05348">arXiv:2208.05348</a> <span> [<a href="https://arxiv.org/pdf/2208.05348">pdf</a>, <a href="https://arxiv.org/format/2208.05348">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="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/10.1051/0004-6361/202244007">10.1051/0004-6361/202244007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First release of Apertif imaging survey data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">Elizabeth A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Denes%2C+H">H. Denes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Kutkin%2C+A">A. Kutkin</a>, <a href="/search/astro-ph?searchtype=author&query=Lucero%2C+D+M">D. M. Lucero</a>, <a href="/search/astro-ph?searchtype=author&query=Morganti%2C+R">R. Morganti</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Oosterloo%2C+T+A">T. A. Oosterloo</a>, <a href="/search/astro-ph?searchtype=author&query=Orru%2C+E">E. Orru</a>, <a href="/search/astro-ph?searchtype=author&query=Schulz%2C+R">R. Schulz</a>, <a href="/search/astro-ph?searchtype=author&query=van+Amesfoort%2C+A+S">A. S. van Amesfoort</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+A">A. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Boersma%2C+O+M">O. M. Boersma</a>, <a href="/search/astro-ph?searchtype=author&query=Bouwhuis%2C+M">M. Bouwhuis</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+R+v+d">R. van den Brink</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">L. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=van+Diepen%2C+G+N+J">G. N. J. van Diepen</a>, <a href="/search/astro-ph?searchtype=author&query=Dijkema%2C+T+J">T. J. Dijkema</a>, <a href="/search/astro-ph?searchtype=author&query=Ebbendorf%2C+N">N. Ebbendorf</a> , et al. (34 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="2208.05348v2-abstract-short" style="display: inline;"> (Abridged) Apertif is a phased-array feed system for WSRT, providing forty instantaneous beams over 300 MHz of bandwidth. A dedicated survey program started on 1 July 2019, with the last observations taken on 28 February 2022. We describe the release of data products from the first year of survey operations, through 30 June 2020. We focus on defining quality control metrics for the processed data… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.05348v2-abstract-full').style.display = 'inline'; document.getElementById('2208.05348v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.05348v2-abstract-full" style="display: none;"> (Abridged) Apertif is a phased-array feed system for WSRT, providing forty instantaneous beams over 300 MHz of bandwidth. A dedicated survey program started on 1 July 2019, with the last observations taken on 28 February 2022. We describe the release of data products from the first year of survey operations, through 30 June 2020. We focus on defining quality control metrics for the processed data products. The Apertif imaging pipeline, Apercal, automatically produces non-primary beam corrected continuum images, polarization images and cubes, and uncleaned spectral line and dirty beam cubes for each beam of an Apertif imaging observation. For this release, processed data products are considered on a beam-by-beam basis within an observation. We validate the continuum images by using metrics that identify deviations from Gaussian noise in the residual images. If the continuum image passes validation, we release all processed data products for a given beam. We apply further validation to the polarization and line data products. We release all raw observational data from the first year of survey observations, for a total of 221 observations of 160 independent target fields, covering approximately one thousand square degrees of sky. Images and cubes are released on a per beam basis, and 3374 beams are released. The median noise in the continuum images is 41.4 uJy/bm, with a slightly lower median noise of 36.9 uJy/bm in the Stokes V polarization image. The median angular resolution is 11.6"/sin(Dec). The median noise for all line cubes, with a spectral resolution of 36.6 kHz, is 1.6 mJy/bm, corresponding to a 3-sigma HI column density sensitivity of 1.8 x 10^20 atoms cm^-2 over 20 km/s (for a median angular resolution of 24" x 15"). We also provide primary beam images for each individual Apertif compound beam. The data are made accessible using a Virtual Observatory interface. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.05348v2-abstract-full').style.display = 'none'; document.getElementById('2208.05348v2-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 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 A&A, updated Figure 1</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 667, A38 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.09662">arXiv:2205.09662</a> <span> [<a href="https://arxiv.org/pdf/2205.09662">pdf</a>, <a href="https://arxiv.org/format/2205.09662">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/10.1051/0004-6361/202244045">10.1051/0004-6361/202244045 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Characterising the Apertif primary beam response </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">H. D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Kutkin%2C+A">A. Kutkin</a>, <a href="/search/astro-ph?searchtype=author&query=Morganti%2C+R">R. Morganti</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Oosterloo%2C+T+A">T. A. Oosterloo</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Ivashina%2C+M+V">M. V. Ivashina</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. M. Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Lucero%2C+D+M">D. M. Lucero</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Mika%2C+%C3%81">脕. Mika</a>, <a href="/search/astro-ph?searchtype=author&query=Norden%2C+M+J">M. J. Norden</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Pisano%2C+D+J">D. J. Pisano</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+R+v+d">R. van den Brink</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Schuur%2C+D">D. van der Schuur</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="2205.09662v2-abstract-short" style="display: inline;"> Context. Phased Array Feeds (PAFs) are multi element receivers in the focal plane of a telescope that make it possible to form simultaneously multiple beams on the sky by combining the complex gains of the individual antenna elements. Recently the Westerbork Synthesis Radio Telescope (WSRT) was upgraded with PAF receivers and carried out several observing programs including two imaging surveys and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.09662v2-abstract-full').style.display = 'inline'; document.getElementById('2205.09662v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.09662v2-abstract-full" style="display: none;"> Context. Phased Array Feeds (PAFs) are multi element receivers in the focal plane of a telescope that make it possible to form simultaneously multiple beams on the sky by combining the complex gains of the individual antenna elements. Recently the Westerbork Synthesis Radio Telescope (WSRT) was upgraded with PAF receivers and carried out several observing programs including two imaging surveys and a time domain survey. The Apertif imaging surveys use a configuration, where 40 partially overlapping compound beams (CBs) are simultaneously formed on the sky and arranged in an approximately rectangular shape. Aims. This manuscript aims to characterise the response of the 40 Apertif CBs to create frequency-resolved, I, XX and YY polarization empirical beam shapes. The measured CB maps can be used for image deconvolution, primary beam correction and mosaicing of Apertif imaging data. Methods. We use drift scan measurements to measure the response of each of the 40 CBs of Apertif. We derive beam maps for all individual beams in I, XX and YY polarisation in 10 or 18 frequency bins over the same bandwidth as the Apertif imaging surveys. We sample the main lobe of the beams and the side lobes up to a radius of 0.6 degrees from the beam centres. In addition, we derive beam maps for each individual WSRT dish as well. Results. We present the frequency and time dependence of the beam shapes and sizes. We compare the compound beam shapes derived with the drift scan method to beam shapes derived with an independent method using a Gaussian Process Regression comparison between the Apertif continuum images and the NRAO VLA Sky Survey (NVSS) catalogue. We find a good agreement between the beam shapes derived with the two independent methods. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.09662v2-abstract-full').style.display = 'none'; document.getElementById('2205.09662v2-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> 2 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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 by A&A, 14 pages, 15 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 667, A40 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.16925">arXiv:2203.16925</a> <span> [<a href="https://arxiv.org/pdf/2203.16925">pdf</a>, <a href="https://arxiv.org/format/2203.16925">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="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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/10.1051/0004-6361/202243201">10.1051/0004-6361/202243201 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Apertif science verification campaign - Characteristics of polarised radio sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+A">A. Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">H. D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Schulz%2C+R">R. Schulz</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">L. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Ivashina%2C+M+V">M. V. Ivashina</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. M. Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Mika%2C+A">A. Mika</a>, <a href="/search/astro-ph?searchtype=author&query=Mulder%2C+H">H. Mulder</a>, <a href="/search/astro-ph?searchtype=author&query=Norden%2C+M+J">M. J. Norden</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Orr%C3%BA%2C+E">E. Orr煤</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiter%2C+M">M. Ruiter</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=van+Leeuwen%2C+J">J. van Leeuwen</a>, <a href="/search/astro-ph?searchtype=author&query=Vermaas%2C+N+J">N. J. Vermaas</a> , et al. (2 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="2203.16925v1-abstract-short" style="display: inline;"> We analyse five early science datasets from the APERture Tile in Focus (Apertif) phased array feed system to verify the polarisation capabilities of Apertif in view of future larger data releases. We aim to characterise the source population of the polarised sky in the L-Band using polarised source information in combination with IR and optical data. We use automatic routines to generate full fiel… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.16925v1-abstract-full').style.display = 'inline'; document.getElementById('2203.16925v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.16925v1-abstract-full" style="display: none;"> We analyse five early science datasets from the APERture Tile in Focus (Apertif) phased array feed system to verify the polarisation capabilities of Apertif in view of future larger data releases. We aim to characterise the source population of the polarised sky in the L-Band using polarised source information in combination with IR and optical data. We use automatic routines to generate full field-of-view Q- and U-cubes and perform RM-Synthesis, source finding, and cross-matching with published radio, optical, and IR data to generate polarised source catalogues. SED-fitting routines were used to determine photometric redshifts, star-formation rates, and galaxy masses. IR colour information was used to classify sources as AGN or star-forming-dominated and early- or late-type. We surveyed an area of 56deg$^2$ and detected 1357 polarised source components in 1170 sources. The fraction of polarised sources is 10.57% with a median fractional polarisation of 4.70$\pm$0.14%. We confirmed the reliability of the Apertif measurements by comparing them with polarised cross-identified NVSS sources. Average RMs of the individual fields lie within the error of the best Milky Way foreground measurements. All of our polarised sources were found to be dominated by AGN activity in the radio regime with most of them being radio-loud (79%) and of the FRII class (87%). The host galaxies of our polarised source sample are dominated by intermediate disc and star-forming disc galaxies. The contribution of star formation to the radio emission is on the order of a few percent for $\approx$10% of the polarised sources while for $\approx$90% it is completely dominated by the AGN. We do not see any change in fractional polarisation for different star-formation rates of the AGN host galaxies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.16925v1-abstract-full').style.display = 'none'; document.getElementById('2203.16925v1-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> 31 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">24 pages, 21 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 663, A103 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.08002">arXiv:2202.08002</a> <span> [<a href="https://arxiv.org/pdf/2202.08002">pdf</a>, <a href="https://arxiv.org/format/2202.08002">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/10.1051/0004-6361/202243339">10.1051/0004-6361/202243339 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A fast radio burst with sub-millisecond quasi-periodic structure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pastor-Marazuela%2C+I">In茅s Pastor-Marazuela</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=Bilous%2C+A">Anna Bilous</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">Liam Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L">Leon Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">Emily Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Straal%2C+S">Samayra Straal</a>, <a href="/search/astro-ph?searchtype=author&query=Vohl%2C+D">Dany Vohl</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=Attema%2C+J">Jisk Attema</a>, <a href="/search/astro-ph?searchtype=author&query=Boersma%2C+O+M">Oliver M. Boersma</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+R+v+d">R. van den Brink</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">H. D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Kutkin%2C+A">A. Kutkin</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. Marcel Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Lucero%2C+D+M">D. M. Lucero</a>, <a href="/search/astro-ph?searchtype=author&query=Mika%2C+%C3%81">脕. Mika</a> , et al. (9 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="2202.08002v1-abstract-short" style="display: inline;"> Fast radio bursts (FRBs) are extragalactic radio transients of extraordinary luminosity. Studying the diverse temporal and spectral behaviour recently observed in a number of FRBs may help determine the nature of the entire class. For example, a fast spinning or highly magnetised neutron star might generate the rotation-powered acceleration required to explain the bright emission. Periodic, sub-se… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08002v1-abstract-full').style.display = 'inline'; document.getElementById('2202.08002v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.08002v1-abstract-full" style="display: none;"> Fast radio bursts (FRBs) are extragalactic radio transients of extraordinary luminosity. Studying the diverse temporal and spectral behaviour recently observed in a number of FRBs may help determine the nature of the entire class. For example, a fast spinning or highly magnetised neutron star might generate the rotation-powered acceleration required to explain the bright emission. Periodic, sub-second components, suggesting such rotation, were recently reported in one FRB, and potentially in two more. Here we report the discovery of FRB 20201020A with Apertif, an FRB showing five components regularly spaced by 0.415 ms. This sub-millisecond structure in FRB 20201020A carries important clues about the progenitor of this FRB specifically, and potentially about that of FRBs in general. We thus contrast its features to the predictions of the main FRB source models. We perform a timing analysis of the FRB 20201020A components to determine the significance of the periodicity. We compare these against the timing properties of the previously reported CHIME FRBs with sub-second quasi-periodic components, and against two Apertif bursts from repeating FRB 20180916B that show complex time-frequency structure. We find the periodicity of FRB 20201020A to be marginally significant at 2.5$蟽$. Its repeating subcomponents cannot be explained as a pulsar rotation since the required spin rate of over 2 kHz exceeds the limits set by typical neutron star equations of state and observations. The fast periodicity is also in conflict with a compact object merger scenario. These quasi-periodic components could, however, be caused by equidistant emitting regions in the magnetosphere of a magnetar. The sub-millisecond spacing of the components in FRB 20201020A, the smallest observed so far in a one-off FRB, may rule out both neutron-star rotation and binary mergers as the direct source of quasi-periodic FRBs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.08002v1-abstract-full').style.display = 'none'; document.getElementById('2202.08002v1-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 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">13 pages, 6 figures, 3 tables, supplementary material. Submitted to 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, A149 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2112.03722">arXiv:2112.03722</a> <span> [<a href="https://arxiv.org/pdf/2112.03722">pdf</a>, <a href="https://arxiv.org/format/2112.03722">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/10.1016/j.ascom.2021.100514">10.1016/j.ascom.2021.100514 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Apercal -- The Apertif Calibration Pipeline </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=Schulz%2C+R">R. Schulz</a>, <a href="/search/astro-ph?searchtype=author&query=Dijkema%2C+T+J">T. J. Dijkema</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Offringa%2C+A+R">A. R. Offringa</a>, <a href="/search/astro-ph?searchtype=author&query=Kutkin%2C+A">A. Kutkin</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Frank%2C+B+S">B. S. Frank</a>, <a href="/search/astro-ph?searchtype=author&query=Vilchez%2C+N+P+E">N. P. E. Vilchez</a>, <a href="/search/astro-ph?searchtype=author&query=Verstappen%2C+J">J. Verstappen</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+K">E. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Denes%2C+H">H. Denes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=Lucero%2C+D">D. Lucero</a>, <a href="/search/astro-ph?searchtype=author&query=Morganti%2C+R">R. Morganti</a>, <a href="/search/astro-ph?searchtype=author&query=Oosterloo%2C+T">T. Oosterloo</a>, <a href="/search/astro-ph?searchtype=author&query=Pisano%2C+D+-">D. -J. Pisano</a>, <a href="/search/astro-ph?searchtype=author&query=Ivashina%2C+M+V">M. V. Ivashina</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L+D">L. D. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. M. Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a> , et al. (11 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="2112.03722v1-abstract-short" style="display: inline;"> Apertif (APERture Tile In Focus) is one of the Square Kilometre Array (SKA) pathfinder facilities. The Apertif project is an upgrade to the 50-year-old Westerbork Synthesis Radio Telescope (WSRT) using phased-array feed technology. The new receivers create 40 individual beams on the sky, achieving an instantaneous sky coverage of 6.5 square degrees. The primary goal of the Apertif Imaging Survey i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.03722v1-abstract-full').style.display = 'inline'; document.getElementById('2112.03722v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2112.03722v1-abstract-full" style="display: none;"> Apertif (APERture Tile In Focus) is one of the Square Kilometre Array (SKA) pathfinder facilities. The Apertif project is an upgrade to the 50-year-old Westerbork Synthesis Radio Telescope (WSRT) using phased-array feed technology. The new receivers create 40 individual beams on the sky, achieving an instantaneous sky coverage of 6.5 square degrees. The primary goal of the Apertif Imaging Survey is to perform a wide survey of 3500 square degrees (AWES) and a medium deep survey of 350 square degrees (AMES) of neutral atomic hydrogen (up to a redshift of 0.26), radio continuum emission and polarisation. Each survey pointing yields 4.6 TB of correlated data. The goal of Apercal is to process this data and fully automatically generate science ready data products for the astronomical community while keeping up with the survey observations. We make use of common astronomical software packages in combination with Python based routines and parallelisation. We use an object oriented module-based approach to ensure easy adaptation of the pipeline. A Jupyter notebook based framework allows user interaction and execution of individual modules as well as a full automatic processing of a complete survey observation. If nothing interrupts processing, we are able to reduce a single pointing survey observation on our five node cluster with 24 physical cores and 256 GB of memory each within 24h keeping up with the speed of the surveys. The quality of the generated images is sufficient for scientific usage for 44 % of the recorded data products with single images reaching dynamic ranges of several thousands. Future improvements will increase this percentage to over 80 %. Our design allowed development of the pipeline in parallel to the commissioning of the Apertif system. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2112.03722v1-abstract-full').style.display = 'none'; document.getElementById('2112.03722v1-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 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">Journal ref:</span> Astronomy and Computing 38 (2022) 100514 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2111.14225">arXiv:2111.14225</a> <span> [<a href="https://arxiv.org/pdf/2111.14225">pdf</a>, <a href="https://arxiv.org/format/2111.14225">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/stab3434">10.1093/mnras/stab3434 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Removal and replacement of interference in tied-array radio pulsar observations using the spectral kurtosis estimator </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">M. Purver</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=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J+W">J. W. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">S. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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="2111.14225v3-abstract-short" style="display: inline;"> We describe how to implement the spectral kurtosis method of interference removal (zapping) on a digitized signal of averaged power values. Spectral kurtosis is a hypothesis test, analogous to the t-test, with a null hypothesis that the amplitudes from which power is formed belong to a `good' distribution -- typically Gaussian with zero mean -- where power values are zapped if the hypothesis is re… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.14225v3-abstract-full').style.display = 'inline'; document.getElementById('2111.14225v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.14225v3-abstract-full" style="display: none;"> We describe how to implement the spectral kurtosis method of interference removal (zapping) on a digitized signal of averaged power values. Spectral kurtosis is a hypothesis test, analogous to the t-test, with a null hypothesis that the amplitudes from which power is formed belong to a `good' distribution -- typically Gaussian with zero mean -- where power values are zapped if the hypothesis is rejected at a specified confidence level. We derive signal-to-noise ratios (SNRs) as a function of amount of zapping for folded radio pulsar observations consisting of a sum of signals from multiple telescopes in independent radio-frequency interference (RFI) environments, comparing four methods to compensate for lost data with coherent (tied-array) and incoherent summation. For coherently summed amplitudes, scaling amplitudes from non-zapped telescopes achieves a higher SNR than replacing zapped amplitudes with artificial noise. For incoherently summed power values, the highest SNR is given by scaling power from non-zapped telescopes to maintain a constant mean. We use spectral kurtosis to clean a tied-array radio pulsar observation by the Large European Array for Pulsars (LEAP): the signal from one telescope is zapped with time and frequency resolutions of 6.25 $渭$s and 0.16 MHz, removing interference along with 0.27 per cent of `good' data, giving an uncertainty of 0.25 $渭$s in pulse time of arrival (TOA) for PSR J1022+1001. We use a single-telescope observation to demonstrate recovery of the pulse profile shape, with 0.6 per cent of data zapped and a reduction from 1.22 to 0.70 $渭$s in TOA uncertainty. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.14225v3-abstract-full').style.display = 'none'; document.getElementById('2111.14225v3-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> 24 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">16 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS, 510, 1597 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.14234">arXiv:2109.14234</a> <span> [<a href="https://arxiv.org/pdf/2109.14234">pdf</a>, <a href="https://arxiv.org/format/2109.14234">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/10.1051/0004-6361/202141739">10.1051/0004-6361/202141739 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Apertif, Phased Array Feeds for the Westerbork Synthesis Radio Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Oosterloo%2C+T+A">T. A. Oosterloo</a>, <a href="/search/astro-ph?searchtype=author&query=Verheijen%2C+M+A+W">M. A. W. Verheijen</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=Braun%2C+R">R. Braun</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=Holties%2C+H">H. Holties</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Kooistra%2C+E">E. Kooistra</a>, <a href="/search/astro-ph?searchtype=author&query=van+Leeuwen%2C+J">J. van Leeuwen</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. M. Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Morganti%2C+R">R. Morganti</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Orr%C3%BA%2C+E">E. Orr煤</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiter%2C+M">M. Ruiter</a>, <a href="/search/astro-ph?searchtype=author&query=Schoenmakers%2C+A+P">A. P. Schoenmakers</a>, <a href="/search/astro-ph?searchtype=author&query=Vermaas%2C+N+J">N. J. Vermaas</a>, <a href="/search/astro-ph?searchtype=author&query=Wijnholds%2C+S+J">S. J. Wijnholds</a>, <a href="/search/astro-ph?searchtype=author&query=van+Amesfoort%2C+A+S">A. S. van Amesfoort</a>, <a href="/search/astro-ph?searchtype=author&query=Arts%2C+M+J">M. J. Arts</a>, <a href="/search/astro-ph?searchtype=author&query=Attema%2C+J+J">J. J. Attema</a>, <a href="/search/astro-ph?searchtype=author&query=Bakker%2C+L">L. Bakker</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a> , et al. (65 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="2109.14234v2-abstract-short" style="display: inline;"> We describe the APERture Tile In Focus (Apertif) system, a phased array feed (PAF) upgrade of the Westerbork Synthesis Radio Telescope which has transformed this telescope into a high-sensitivity, wide field-of-view L-band imaging and transient survey instrument. Using novel PAF technology, up to 40 partially overlapping beams can be formed on the sky simultaneously, significantly increasing the s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.14234v2-abstract-full').style.display = 'inline'; document.getElementById('2109.14234v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.14234v2-abstract-full" style="display: none;"> We describe the APERture Tile In Focus (Apertif) system, a phased array feed (PAF) upgrade of the Westerbork Synthesis Radio Telescope which has transformed this telescope into a high-sensitivity, wide field-of-view L-band imaging and transient survey instrument. Using novel PAF technology, up to 40 partially overlapping beams can be formed on the sky simultaneously, significantly increasing the survey speed of the telescope. With this upgraded instrument, an imaging survey covering an area of 2300 deg2 is being performed which will deliver both continuum and spectral line data sets, of which the first data has been publicly released. In addition, a time domain transient and pulsar survey covering 15,000 deg2 is in progress. An overview of the Apertif science drivers, hardware and software of the upgraded telescope is presented, along with its key performance characteristics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.14234v2-abstract-full').style.display = 'none'; document.getElementById('2109.14234v2-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> 30 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">29 pages, 42 figures, accepted for publication 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 658, A146 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.08500">arXiv:2109.08500</a> <span> [<a href="https://arxiv.org/pdf/2109.08500">pdf</a>, <a href="https://arxiv.org/format/2109.08500">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/10.1051/0004-6361/202142242">10.1051/0004-6361/202142242 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Dual-frequency single-pulse study of PSR B0950+08 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bilous%2C+A+V">A. V. Bilous</a>, <a href="/search/astro-ph?searchtype=author&query=Griessmeier%2C+J+M">J. M. Griessmeier</a>, <a href="/search/astro-ph?searchtype=author&query=Pennucci%2C+T">T. Pennucci</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+Z">Z. Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Bondonneau%2C+L">L. Bondonneau</a>, <a href="/search/astro-ph?searchtype=author&query=Kondratiev%2C+V">V. Kondratiev</a>, <a href="/search/astro-ph?searchtype=author&query=van+Leeuwen%2C+J">J. van Leeuwen</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">L. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">E. Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Vohl%2C+D">D. Vohl</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J+W">J. W. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Shaifullah%2C+G">G. Shaifullah</a>, <a href="/search/astro-ph?searchtype=author&query=Theureau%2C+G">G. Theureau</a>, <a href="/search/astro-ph?searchtype=author&query=Ulyanov%2C+O+M">O. M. Ulyanov</a>, <a href="/search/astro-ph?searchtype=author&query=Cecconi%2C+B">B. Cecconi</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H">A. H. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Corbel%2C+S">S. Corbel</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=Denes%2C+H">H. Denes</a>, <a href="/search/astro-ph?searchtype=author&query=Girard%2C+J+N">J. N. Girard</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Ivashina%2C+M">M. Ivashina</a> , et al. (11 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="2109.08500v2-abstract-short" style="display: inline;"> PSR B0950+08 is a bright non-recycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR) and 1.4 GHz (Westerbork Synthesis Radio Telescope), we review the properties of these single pulses. We conclude that they are more similar to ordinary pulses of radio emission than to a special kind of short and bright… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.08500v2-abstract-full').style.display = 'inline'; document.getElementById('2109.08500v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.08500v2-abstract-full" style="display: none;"> PSR B0950+08 is a bright non-recycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR) and 1.4 GHz (Westerbork Synthesis Radio Telescope), we review the properties of these single pulses. We conclude that they are more similar to ordinary pulses of radio emission than to a special kind of short and bright Giant Pulses, observed from only a handful of pulsars. We argue that temporal variation of properties of interstellar medium along the line of sight to this nearby pulsar, namely the fluctuating size of decorrelation bandwidth of diffractive scintillation makes important contribution to observed single-pulse fluence variability. We further present interesting structures in the low-frequency single-pulse spectra that resemble the "sad trombones" seen in Fast Radio Bursts (FRBs); although for PSR B0950+08 the upward frequency drift is also routinely present. We explain these spectral features with radius-to-frequency mapping, similar to the model developed by Wang et al. (2019) for FRBs. Finally, we speculate that microsecond-scale fluence variability of the general pulsar population remains poorly known, and that its further study may bring important clues about the nature of FRBs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.08500v2-abstract-full').style.display = 'none'; document.getElementById('2109.08500v2-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 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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 by A&A. This version includes a number of minor corrections, including corrected FRB luminosities on the time-luminosity phase-space plot for radio pulses from neutron stars and repeating FRBs</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 658, A143 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.04280">arXiv:2104.04280</a> <span> [<a href="https://arxiv.org/pdf/2104.04280">pdf</a>, <a href="https://arxiv.org/format/2104.04280">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/10.1051/0004-6361/202140578">10.1051/0004-6361/202140578 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A search for radio emission from double-neutron star merger GW190425 using Apertif </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Boersma%2C+O">Oliv茅r Boersma</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=Adams%2C+E+A+K">Elizabeth A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">Bj枚rn Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=Kutkin%2C+A">Alexander Kutkin</a>, <a href="/search/astro-ph?searchtype=author&query=Oosterloo%2C+T">Tom Oosterloo</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+R+v+d">R. van den Brink</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">L. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">H. D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">K. M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+J+M">J. M. van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">B. Hut</a>, <a href="/search/astro-ph?searchtype=author&query=Ivashina%2C+M">M. Ivashina</a>, <a href="/search/astro-ph?searchtype=author&query=Loose%2C+G+M">G. M. Loose</a>, <a href="/search/astro-ph?searchtype=author&query=Lucero%2C+D+M">D. M. Lucero</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Mika%2C+%C3%81">脕. Mika</a>, <a href="/search/astro-ph?searchtype=author&query=Moss%2C+V+A">V. A. Moss</a>, <a href="/search/astro-ph?searchtype=author&query=Mulder%2C+H">H. Mulder</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Ruiter%2C+M">M. Ruiter</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Schuur%2C+D">D. van der Schuur</a> , et al. (4 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="2104.04280v1-abstract-short" style="display: inline;"> Detection of the electromagnetic emission from coalescing binary neutron stars (BNS) is important for understanding the merger and afterglow. We present a search for a radio counterpart to the gravitational-wave source GW190425, a BNS merger, using Apertif on the Westerbork Synthesis Radio Telescope (WSRT). We observe a field of high probability in the associated localisation region for 3 epochs a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04280v1-abstract-full').style.display = 'inline'; document.getElementById('2104.04280v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.04280v1-abstract-full" style="display: none;"> Detection of the electromagnetic emission from coalescing binary neutron stars (BNS) is important for understanding the merger and afterglow. We present a search for a radio counterpart to the gravitational-wave source GW190425, a BNS merger, using Apertif on the Westerbork Synthesis Radio Telescope (WSRT). We observe a field of high probability in the associated localisation region for 3 epochs at 68, 90 and 109 days post merger. We identify all sources that exhibit flux variations consistent with the expected afterglow emission of GW190425. We also look for possible transients. These are sources which are only present in one epoch. In addition, we quantify our ability to search for radio afterglows in fourth and future observing runs of the gravitational-wave detector network using Monte Carlo simulations. We found 25 afterglow candidates based on their variability. None of these could be associated with a possible host galaxy at the luminosity distance of GW190425. We also found 55 transient afterglow candidates that were only detected in one epoch. All turned out to be image artefacts. In the fourth observing run, we predict that up to three afterglows will be detectable by Apertif. While we did not find a source related to the afterglow emission of GW190425, the search validates our methods for future searches of radio afterglows. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.04280v1-abstract-full').style.display = 'none'; document.getElementById('2104.04280v1-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 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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, 7 figures, accepted for publication</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 650, A131 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.08348">arXiv:2012.08348</a> <span> [<a href="https://arxiv.org/pdf/2012.08348">pdf</a>, <a href="https://arxiv.org/format/2012.08348">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/10.1038/s41586-021-03724-8">10.1038/s41586-021-03724-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Chromatic periodic activity down to 120 MHz in a Fast Radio Burst </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pastor-Marazuela%2C+I">In茅s Pastor-Marazuela</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">Liam Connor</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=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=ter+Veen%2C+S">Sander ter Veen</a>, <a href="/search/astro-ph?searchtype=author&query=Bilous%2C+A">Anna Bilous</a>, <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L">Leon Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">Emily Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Straal%2C+S">Samayra Straal</a>, <a href="/search/astro-ph?searchtype=author&query=Vohl%2C+D">Dany Vohl</a>, <a href="/search/astro-ph?searchtype=author&query=Attema%2C+J">Jisk Attema</a>, <a href="/search/astro-ph?searchtype=author&query=Boersma%2C+O+M">Oliver M. Boersma</a>, <a href="/search/astro-ph?searchtype=author&query=Kooistra%2C+E">Eric Kooistra</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Schuur%2C+D">Daniel van der Schuur</a>, <a href="/search/astro-ph?searchtype=author&query=Sclocco%2C+A">Alessio Sclocco</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">Roy Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">Elizabeth A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">Bj枚rn Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">Willem J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">Arthur H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">Sieds Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">Helga D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+K+M">Kelley M. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Hulst%2C+T">Thijs van der Hulst</a>, <a href="/search/astro-ph?searchtype=author&query=Hut%2C+B">Boudewijn Hut</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="2012.08348v1-abstract-short" style="display: inline;"> Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, millisecond-duration bursts. FRBs have thus far been detected between 300 MHz and 8 GHz, but lower-frequency emission has remained elusive. A subset of FRBs is known to repeat, and one of those sources, FRB 20180916B, does so wit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.08348v1-abstract-full').style.display = 'inline'; document.getElementById('2012.08348v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.08348v1-abstract-full" style="display: none;"> Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, millisecond-duration bursts. FRBs have thus far been detected between 300 MHz and 8 GHz, but lower-frequency emission has remained elusive. A subset of FRBs is known to repeat, and one of those sources, FRB 20180916B, does so with a 16.3 day activity period. Using simultaneous Apertif and LOFAR data, we show that FRB 20180916B emits down to 120 MHz, and that its activity window is both narrower and earlier at higher frequencies. Binary wind interaction models predict a narrower periodic activity window at lower frequencies, which is the opposite of our observations. Our detections establish that low-frequency FRB emission can escape the local medium. For bursts of the same fluence, FRB 20180916B is more active below 200 MHz than at 1.4 GHz. Combining our results with previous upper-limits on the all-sky FRB rate at 150 MHz, we find that there are 3-450 FRBs/sky/day above 50 Jy ms at 90% confidence. We are able to rule out the scenario in which companion winds cause FRB periodicity. We also demonstrate that some FRBs live in clean environments that do not absorb or scatter low-frequency radiation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.08348v1-abstract-full').style.display = 'none'; document.getElementById('2012.08348v1-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 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2020. </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">50 pages, 14 figures, 3 tables, submitted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2002.01399">arXiv:2002.01399</a> <span> [<a href="https://arxiv.org/pdf/2002.01399">pdf</a>, <a href="https://arxiv.org/format/2002.01399">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/staa3009">10.1093/mnras/staa3009 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A bright, high rotation-measure FRB that skewers the M33 halo </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">Liam Connor</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=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">E. Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Yogesh Maan</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Attema%2C+J+J">J. J. Attema</a>, <a href="/search/astro-ph?searchtype=author&query=Bast%2C+J+E">J. E. Bast</a>, <a href="/search/astro-ph?searchtype=author&query=Boersma%2C+O+M">O. M. Boersma</a>, <a href="/search/astro-ph?searchtype=author&query=D%C3%A9nes%2C+H">H. D茅nes</a>, <a href="/search/astro-ph?searchtype=author&query=Gardenier%2C+D+W">D. W. Gardenier</a>, <a href="/search/astro-ph?searchtype=author&query=Hargreaves%2C+J+E">J. E. Hargreaves</a>, <a href="/search/astro-ph?searchtype=author&query=Kooistra%2C+E">E. Kooistra</a>, <a href="/search/astro-ph?searchtype=author&query=Pastor-Marazuela%2C+I">I. Pastor-Marazuela</a>, <a href="/search/astro-ph?searchtype=author&query=Schulz%2C+R">R. Schulz</a>, <a href="/search/astro-ph?searchtype=author&query=Sclocco%2C+A">A. Sclocco</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Straal%2C+S+M">S. M. Straal</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Schuur%2C+D">D. van der Schuur</a>, <a href="/search/astro-ph?searchtype=author&query=Vohl%2C+D">Dany Vohl</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a> , et al. (15 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="2002.01399v2-abstract-short" style="display: inline;"> We report the detection of a bright fast radio burst, FRB\,191108, with Apertif on the Westerbork Synthesis Radio Telescope (WSRT). The interferometer allows us to localise the FRB to a narrow $5\arcsec\times7\arcmin$ ellipse by employing both multibeam information within the Apertif phased-array feed (PAF) beam pattern, and across different tied-array beams. The resulting sight line passes close… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.01399v2-abstract-full').style.display = 'inline'; document.getElementById('2002.01399v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2002.01399v2-abstract-full" style="display: none;"> We report the detection of a bright fast radio burst, FRB\,191108, with Apertif on the Westerbork Synthesis Radio Telescope (WSRT). The interferometer allows us to localise the FRB to a narrow $5\arcsec\times7\arcmin$ ellipse by employing both multibeam information within the Apertif phased-array feed (PAF) beam pattern, and across different tied-array beams. The resulting sight line passes close to Local Group galaxy M33, with an impact parameter of only 18\,kpc with respect to the core. It also traverses the much larger circumgalactic medium of M31, the Andromeda Galaxy. We find that the shared plasma of the Local Group galaxies could contribute $\sim$10\% of its dispersion measure of 588\,pc\,cm$^{-3}$. FRB\,191108 has a Faraday rotation measure of +474\,$\pm\,3$\,rad\,m$^{-2}$, which is too large to be explained by either the Milky Way or the intergalactic medium. Based on the more moderate RMs of other extragalactic sources that traverse the halo of M33, we conclude that the dense magnetised plasma resides in the host galaxy. The FRB exhibits frequency structure on two scales, one that is consistent with quenched Galactic scintillation and broader spectral structure with $螖谓\approx40$\,MHz. If the latter is due to scattering in the shared M33/M31 CGM, our results constrain the Local Group plasma environment. We found no accompanying persistent radio sources in the Apertif imaging survey data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2002.01399v2-abstract-full').style.display = 'none'; document.getElementById('2002.01399v2-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 4 February, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.12217">arXiv:1912.12217</a> <span> [<a href="https://arxiv.org/pdf/1912.12217">pdf</a>, <a href="https://arxiv.org/format/1912.12217">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/10.1051/0004-6361/201937422">10.1051/0004-6361/201937422 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Repeating fast radio bursts with WSRT/Apertif </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Oostrum%2C+L+C">L. C. Oostrum</a>, <a href="/search/astro-ph?searchtype=author&query=Maan%2C+Y">Y. Maan</a>, <a href="/search/astro-ph?searchtype=author&query=van+Leeuwen%2C+J">J. van Leeuwen</a>, <a href="/search/astro-ph?searchtype=author&query=Connor%2C+L">L. Connor</a>, <a href="/search/astro-ph?searchtype=author&query=Petroff%2C+E">E. Petroff</a>, <a href="/search/astro-ph?searchtype=author&query=Attema%2C+J+J">J. J. Attema</a>, <a href="/search/astro-ph?searchtype=author&query=Bast%2C+J+E">J. E. Bast</a>, <a href="/search/astro-ph?searchtype=author&query=Gardenier%2C+D+W">D. W. Gardenier</a>, <a href="/search/astro-ph?searchtype=author&query=Hargreaves%2C+J+E">J. E. Hargreaves</a>, <a href="/search/astro-ph?searchtype=author&query=Kooistra%2C+E">E. Kooistra</a>, <a href="/search/astro-ph?searchtype=author&query=van+der+Schuur%2C+D">D. van der Schuur</a>, <a href="/search/astro-ph?searchtype=author&query=Sclocco%2C+A">A. Sclocco</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Straal%2C+S+M">S. M. Straal</a>, <a href="/search/astro-ph?searchtype=author&query=ter+Veen%2C+S">S. ter Veen</a>, <a href="/search/astro-ph?searchtype=author&query=Vohl%2C+D">D. Vohl</a>, <a href="/search/astro-ph?searchtype=author&query=Adams%2C+E+A+K">E. A. K. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Adebahr%2C+B">B. Adebahr</a>, <a href="/search/astro-ph?searchtype=author&query=de+Blok%2C+W+J+G">W. J. G. de Blok</a>, <a href="/search/astro-ph?searchtype=author&query=Brink%2C+R+H+v+d">R. H. van den Brink</a>, <a href="/search/astro-ph?searchtype=author&query=van+Cappellen%2C+W+A">W. A. van Cappellen</a>, <a href="/search/astro-ph?searchtype=author&query=Coolen%2C+A+H+W+M">A. H. W. M. Coolen</a>, <a href="/search/astro-ph?searchtype=author&query=Damstra%2C+S">S. Damstra</a>, <a href="/search/astro-ph?searchtype=author&query=van+Diepen%2C+G+N+J">G. N. J. van Diepen</a>, <a href="/search/astro-ph?searchtype=author&query=Frank%2C+B+S">B. S. Frank</a> , et al. (18 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="1912.12217v2-abstract-short" style="display: inline;"> Repeating fast radio bursts (FRBs) present excellent opportunities to identify FRB progenitors and host environments, as well as decipher the underlying emission mechanism. Detailed studies of repeating FRBs might also hold clues to the origin of FRBs as a population. We aim to detect the first two repeating FRBs: FRB 121102 (R1) and FRB 180814.J0422+73 (R2), and characterise their repeat statisti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.12217v2-abstract-full').style.display = 'inline'; document.getElementById('1912.12217v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.12217v2-abstract-full" style="display: none;"> Repeating fast radio bursts (FRBs) present excellent opportunities to identify FRB progenitors and host environments, as well as decipher the underlying emission mechanism. Detailed studies of repeating FRBs might also hold clues to the origin of FRBs as a population. We aim to detect the first two repeating FRBs: FRB 121102 (R1) and FRB 180814.J0422+73 (R2), and characterise their repeat statistics. We also want to significantly improve the sky localisation of R2. We use the Westerbork Synthesis Radio Telescope to conduct extensive follow-up of these two repeating FRBs. The new phased-array feed system, Apertif, allows covering the entire sky position uncertainty of R2 with fine spatial resolution in one pointing. We characterise the energy distribution and the clustering of detected R1 bursts. We detected 30 bursts from R1. Our measurements indicate a dispersion measure of 563.5(2) pc cm$^{-3}$, suggesting a significant increase in DM over the past few years. We place an upper limit of 8% on the linear polarisation fraction of the brightest burst. We did not detect any bursts from R2. A single power-law might not fit the R1 burst energy distribution across the full energy range or widely separated detections. Our observations provide improved constraints on the clustering of R1 bursts. Our stringent upper limits on the linear polarisation fraction imply a significant depolarisation, either intrinsic to the emission mechanism or caused by the intervening medium, at 1400 MHz that is not observed at higher frequencies. The non-detection of any bursts from R2 implies either a highly clustered nature of the bursts, a steep spectral index, or a combination of both. Alternatively, R2 has turned off completely, either permanently or for an extended period of time. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.12217v2-abstract-full').style.display = 'none'; document.getElementById('1912.12217v2-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 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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, 7 figures, submitted to 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 635, A61 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.00634">arXiv:1911.00634</a> <span> [<a href="https://arxiv.org/pdf/1911.00634">pdf</a>, <a href="https://arxiv.org/format/1911.00634">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/10.1051/0004-6361/201833555">10.1051/0004-6361/201833555 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Statistics of VHE gamma-Rays in Temporal Association with Radio Giant Pulses from the Crab Pulsar </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=MAGIC+Collaboration"> MAGIC Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Ahnen%2C+M+L">M. L. Ahnen</a>, <a href="/search/astro-ph?searchtype=author&query=Ansoldi%2C+S">S. Ansoldi</a>, <a href="/search/astro-ph?searchtype=author&query=Antonelli%2C+L+A">L. A. Antonelli</a>, <a href="/search/astro-ph?searchtype=author&query=Arcaro%2C+C">C. Arcaro</a>, <a href="/search/astro-ph?searchtype=author&query=Babi%C4%87%2C+A">A. Babi膰</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+B">B. Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Bangale%2C+P">P. Bangale</a>, <a href="/search/astro-ph?searchtype=author&query=de+Almeida%2C+U+B">U. Barres de Almeida</a>, <a href="/search/astro-ph?searchtype=author&query=Barrio%2C+J+A">J. A. Barrio</a>, <a href="/search/astro-ph?searchtype=author&query=Gonz%C3%A1lez%2C+J+B">J. Becerra Gonz谩lez</a>, <a href="/search/astro-ph?searchtype=author&query=Bednarek%2C+W">W. Bednarek</a>, <a href="/search/astro-ph?searchtype=author&query=Bernardini%2C+E">E. Bernardini</a>, <a href="/search/astro-ph?searchtype=author&query=Berti%2C+A">A. Berti</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+W">W. Bhattacharyya</a>, <a href="/search/astro-ph?searchtype=author&query=Biasuzzi%2C+B">B. Biasuzzi</a>, <a href="/search/astro-ph?searchtype=author&query=Biland%2C+A">A. Biland</a>, <a href="/search/astro-ph?searchtype=author&query=Blanch%2C+O">O. Blanch</a>, <a href="/search/astro-ph?searchtype=author&query=Bonnoli%2C+G">G. Bonnoli</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+R">R. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+A">A. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+A">A. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Colak%2C+S+M">S. M. Colak</a>, <a href="/search/astro-ph?searchtype=author&query=Colin%2C+P">P. Colin</a>, <a href="/search/astro-ph?searchtype=author&query=Colombo%2C+E">E. Colombo</a> , et al. (124 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="1911.00634v2-abstract-short" style="display: inline;"> The aim of this study is to search for evidence of a common emission engine between radio giant pulses (GPs) and very-high-energy (VHE, E>100 GeV) gamma-rays from the Crab pulsar. 16 hours of simultaneous observations of the Crab pulsar at 1.4 GHz with the Effelsberg radio telescope and the Westerbork Synthesis Radio Telescope (WSRT), and at energies above 60 GeV with the Major Atmospheric Gamma-r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.00634v2-abstract-full').style.display = 'inline'; document.getElementById('1911.00634v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.00634v2-abstract-full" style="display: none;"> The aim of this study is to search for evidence of a common emission engine between radio giant pulses (GPs) and very-high-energy (VHE, E>100 GeV) gamma-rays from the Crab pulsar. 16 hours of simultaneous observations of the Crab pulsar at 1.4 GHz with the Effelsberg radio telescope and the Westerbork Synthesis Radio Telescope (WSRT), and at energies above 60 GeV with the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes were performed. We searched for a statistical correlation between the radio and VHE gamma-ray emission with search windows of different lengths and different time lags to the arrival times of a radio GP. A dedicated search for an enhancement in the number of VHE gamma-rays correlated with the occurrence of radio GPs was carried out separately for the P1 and P2 phase ranges respectively. 99444 radio GPs have been detected in the radio data sample. We find no significant correlation between the GPs and VHE photons in any of the search windows. Depending on phase cuts and the chosen search windows we find upper limits at 95% confidence level on an increase in VHE gamma-ray events correlated with radio GPs between 7% and 61% of the average Crab pulsar VHE flux for the P1 and P2 phase ranges respectively. This puts upper limits on the flux increase during a radio GP of 12% to 2900% (depending on search window duration and phase cuts) of the pulsed VHE flux. This is the most stringent upper limit on a correlation between gamma-ray emission and radio GPs reported so far.} <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.00634v2-abstract-full').style.display = 'none'; document.getElementById('1911.00634v2-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> 31 January, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 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">15 pages, 7 figures, accepted for publication by Astronomy and Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 634, A25 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.02856">arXiv:1811.02856</a> <span> [<a href="https://arxiv.org/pdf/1811.02856">pdf</a>, <a href="https://arxiv.org/format/1811.02856">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/sty3058">10.1093/mnras/sty3058 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A detailed study of giant pulses from PSR B1937+21 using the Large European Array for Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J+W">J. W. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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=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=Gaikwad%2C+M">M. Gaikwad</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S+A">S. A. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+L">L. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W+W">W. W. Zhu</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="1811.02856v1-abstract-short" style="display: inline;"> We have studied 4265 giant pulses (GPs) from the millisecond pulsar B1937+21; the largest-ever sample gathered for this pulsar, in observations made with the Large European Array for Pulsars. The pulse energy distribution of GPs associated with the interpulse are well-described by a power law, with index $伪= -3.99 \pm 0.04$, while those associated with the main pulse are best-described by a broken… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02856v1-abstract-full').style.display = 'inline'; document.getElementById('1811.02856v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.02856v1-abstract-full" style="display: none;"> We have studied 4265 giant pulses (GPs) from the millisecond pulsar B1937+21; the largest-ever sample gathered for this pulsar, in observations made with the Large European Array for Pulsars. The pulse energy distribution of GPs associated with the interpulse are well-described by a power law, with index $伪= -3.99 \pm 0.04$, while those associated with the main pulse are best-described by a broken power law, with the break occurring at $\sim7$ Jy $渭$s, with power law indices $伪_{\text{low}} = -3.48 \pm 0.04$ and $伪_{\text{high}} = -2.10 \pm 0.09$. The modulation indices of the GP emission are measured, which are found to vary by $\sim0.5$ at pulse phases close to the centre of the GP phase distributions. We find the frequency-resolved structure of GPs to vary significantly, and in a manner that cannot be attributed to the interstellar medium influence on the observed pulses. We examine the distribution of polarisation fractions of the GPs and find no correlation between GP emission phase and fractional polarisation. We use the GPs to time PSR B1937+21 and although the achievable time of arrival precision of the GPs is approximately a factor of two greater than that of the average pulse profile, there is a negligible difference in the precision of the overall timing solution when using the GPs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02856v1-abstract-full').style.display = 'none'; document.getElementById('1811.02856v1-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">20 pages, 21 figures, 3 tables, 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/1802.09206">arXiv:1802.09206</a> <span> [<a href="https://arxiv.org/pdf/1802.09206">pdf</a>, <a href="https://arxiv.org/ps/1802.09206">ps</a>, <a href="https://arxiv.org/format/1802.09206">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/sty2905">10.1093/mnras/sty2905 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Tests of Gravitational Symmetries with Pulsar Binary J1713+0747 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W+W">W. W. Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Wex%2C+N">N. Wex</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=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P+B">P. B. Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Ellis%2C+J+A">J. A. Ellis</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Krieger%2C+A">A. Krieger</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Nice%2C+D+J">D. J. Nice</a>, <a href="/search/astro-ph?searchtype=author&query=Ransom%2C+S+M">S. M. Ransom</a>, <a href="/search/astro-ph?searchtype=author&query=Stairs%2C+I+H">I. H. Stairs</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Arzoumanian%2C+Z">Z. Arzoumanian</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=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Crowter%2C+K">K. Crowter</a>, <a href="/search/astro-ph?searchtype=author&query=Dolch%2C+T">T. Dolch</a>, <a href="/search/astro-ph?searchtype=author&query=Ferdman%2C+R+D">R. D. Ferdman</a>, <a href="/search/astro-ph?searchtype=author&query=Fonseca%2C+E">E. Fonseca</a>, <a href="/search/astro-ph?searchtype=author&query=Gonzalez%2C+M+E">M. E. Gonzalez</a> , et al. (28 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="1802.09206v1-abstract-short" style="display: inline;"> Symmetries play an important role in modern theories of gravity. The strong equivalence principle (SEP) constitutes a collection of gravitational symmetries which are all implemented by general relativity. Alternative theories, however, are generally expected to violate some aspects of SEP. We test three aspects of SEP using observed change rates in the orbital period and eccentricity of binary pu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.09206v1-abstract-full').style.display = 'inline'; document.getElementById('1802.09206v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1802.09206v1-abstract-full" style="display: none;"> Symmetries play an important role in modern theories of gravity. The strong equivalence principle (SEP) constitutes a collection of gravitational symmetries which are all implemented by general relativity. Alternative theories, however, are generally expected to violate some aspects of SEP. We test three aspects of SEP using observed change rates in the orbital period and eccentricity of binary pulsar J1713+0747: 1. the gravitational constant's constancy as part of locational invariance of gravitation; 2. the post-Newtonian parameter $\hat伪_3$ in gravitational Lorentz invariance; 3. the universality of free fall (UFF) for strongly self-gravitating bodies. Based on the pulsar timing result of the combined dataset from the North American Nanohertz Gravitational Observatory (NANOGrav) and the European Pulsar Timing Array (EPTA), we find $\dot{G}/G = (-0.1 \pm 0.9) \times 10^{-12}\,{\rm yr}^{-1}$, which is weaker than Solar system limits, but applies for strongly self-gravitating objects. Furthermore, we obtain the constraints $|螖|< 0.002$ for the UFF test and $-3\times10^{-20} < \hat伪_3 < 4\times10^{-20}$ at 95% confidence. These are the first direct UFF and $\hat伪_3$ tests based on pulsar binaries, and they overcome various limitations of previous tests. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1802.09206v1-abstract-full').style.display = 'none'; document.getElementById('1802.09206v1-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 February, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">11 pages, 6 figures, and 1 table; submitted to 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/1712.02343">arXiv:1712.02343</a> <span> [<a href="https://arxiv.org/pdf/1712.02343">pdf</a>, <a href="https://arxiv.org/ps/1712.02343">ps</a>, <a href="https://arxiv.org/format/1712.02343">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/S1743921317009462">10.1017/S1743921317009462 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pulsar science with data from the Large European Array for Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J+W">J. W. McKee</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=Chen%2C+S">S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Gaikwad%2C+M">M. Gaikwad</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S+A">S. A. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+L">L. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W+W">W. W. Zhu</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="1712.02343v1-abstract-short" style="display: inline;"> The Large European Array for Pulsars (LEAP) is a European Pulsar Timing Array project that combines the Lovell, Effelsberg, Nan莽ay, Sardinia, and Westerbork radio telescopes into a single tied-array, and makes monthly observations of a set of millisecond pulsars (MSPs). The overview of our experiment is presented in Bassa et al. (2016). Baseband data are recorded at a central frequency of 1396 MHz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.02343v1-abstract-full').style.display = 'inline'; document.getElementById('1712.02343v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.02343v1-abstract-full" style="display: none;"> The Large European Array for Pulsars (LEAP) is a European Pulsar Timing Array project that combines the Lovell, Effelsberg, Nan莽ay, Sardinia, and Westerbork radio telescopes into a single tied-array, and makes monthly observations of a set of millisecond pulsars (MSPs). The overview of our experiment is presented in Bassa et al. (2016). Baseband data are recorded at a central frequency of 1396 MHz and a bandwidth of 128 MHz at each telescope, and are correlated offline on a cluster at Jodrell Bank Observatory using a purpose-built correlator, detailed in Smits et al. (2017). LEAP offers a substantial increase in sensitivity over that of the individual telescopes, and can operate in timing and imaging modes (notably in observations of the galactic centre radio magnetar; Wucknitz 2015). To date, 4 years of observations have been reduced. Here, we report on the scientific projects which have made use of LEAP data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.02343v1-abstract-full').style.display = 'none'; document.getElementById('1712.02343v1-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 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">2 pages, 1 figure, accepted for publication in the proceedings of IAU Symposium 337 - Pulsar Astrophysics: The Next Fifty Years</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.06438">arXiv:1703.06438</a> <span> [<a href="https://arxiv.org/pdf/1703.06438">pdf</a>, <a href="https://arxiv.org/ps/1703.06438">ps</a>, <a href="https://arxiv.org/format/1703.06438">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> <p class="title is-5 mathjax"> The beamformer and correlator for the Large European Array for Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</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=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J">J. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">M. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">S. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W+W">W. W. Zhu</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="1703.06438v1-abstract-short" style="display: inline;"> The Large European Array for Pulsars combines Europe's largest radio telescopes to form a tied-array telescope that provides high signal-to-noise observations of millisecond pulsars (MSPs) with the objective to increase the sensitivity of detecting low-frequency gravitational waves. As part of this endeavor we have developed a software correlator and beamformer which enables the formation of a tie… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.06438v1-abstract-full').style.display = 'inline'; document.getElementById('1703.06438v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.06438v1-abstract-full" style="display: none;"> The Large European Array for Pulsars combines Europe's largest radio telescopes to form a tied-array telescope that provides high signal-to-noise observations of millisecond pulsars (MSPs) with the objective to increase the sensitivity of detecting low-frequency gravitational waves. As part of this endeavor we have developed a software correlator and beamformer which enables the formation of a tied-array beam from the raw voltages from each of telescopes. We explain the concepts and techniques involved in the process of adding the raw voltages coherently. We further present the software processing pipeline that is specifically designed to deal with data from widely spaced, inhomogeneous radio telescopes and describe the steps involved in preparing, correlating and creating the tied-array beam. This includes polarization calibration, bandpass correction, frequency dependent phase correction, interference mitigation and pulsar gating. A link is provided where the software can be obtained. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.06438v1-abstract-full').style.display = 'none'; document.getElementById('1703.06438v1-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 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">10 pages, 6 figures, accepted for publication in Astronomy and Computing</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1609.00188">arXiv:1609.00188</a> <span> [<a href="https://arxiv.org/pdf/1609.00188">pdf</a>, <a href="https://arxiv.org/ps/1609.00188">ps</a>, <a href="https://arxiv.org/format/1609.00188">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="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/10.1093/mnras/stw2223">10.1093/mnras/stw2223 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variability, polarimetry, and timing properties of single pulses from PSR J1713+0747 using the Large European Array for Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</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=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J">J. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">M. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">S. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Weltevrede%2C+P">P. Weltevrede</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W+W">W. W. Zhu</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="1609.00188v1-abstract-short" style="display: inline;"> Single pulses preserve information about the pulsar radio emission and propagation in the pulsar magnetosphere, and understanding the behaviour of their variability is essential for estimating the fundamental limit on the achievable pulsar timing precision. Here we report the findings of our analysis of single pulses from PSR J1713+0747 with data collected by the Large European Array for Pulsars (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.00188v1-abstract-full').style.display = 'inline'; document.getElementById('1609.00188v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1609.00188v1-abstract-full" style="display: none;"> Single pulses preserve information about the pulsar radio emission and propagation in the pulsar magnetosphere, and understanding the behaviour of their variability is essential for estimating the fundamental limit on the achievable pulsar timing precision. Here we report the findings of our analysis of single pulses from PSR J1713+0747 with data collected by the Large European Array for Pulsars (LEAP). We present statistical studies of the pulse properties that include distributions of their energy, phase and width. Two modes of systematic sub-pulse drifting have been detected, with a periodicity of 7 and 3 pulse periods. The two modes appear at different ranges of pulse longitude but overlap under the main peak of the integrated profile. No evidence for pulse micro-structure is seen with a time resolution down to 140 ns. In addition, we show that the fractional polarisation of single pulses increases with their pulse peak flux density. By mapping the probability density of linear polarisation position angle with pulse longitude, we reveal the existence of two orthogonal polarisation modes. Finally, we find that the resulting phase jitter of integrated profiles caused by single pulse variability can be described by a Gaussian probability distribution only when at least 100 pulses are used for integration. Pulses of different flux densities and widths contribute approximately equally to the phase jitter, and no improvement on timing precision is achieved by using a sub-set of pulses with a specific range of flux density or width. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1609.00188v1-abstract-full').style.display = 'none'; document.getElementById('1609.00188v1-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, 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">11 pages, 14 figures, 2 tables, 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/1608.01839">arXiv:1608.01839</a> <span> [<a href="https://arxiv.org/pdf/1608.01839">pdf</a>, <a href="https://arxiv.org/ps/1608.01839">ps</a>, <a href="https://arxiv.org/format/1608.01839">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> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> Pulsar observations with European telescopes for testing gravity and detecting gravitational waves </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</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=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K">K. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J">J. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">M. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">S. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+W">W. Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Concu%2C+R">R. Concu</a>, <a href="/search/astro-ph?searchtype=author&query=Melis%2C+A">A. Melis</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Casu%2C+S">S. Casu</a>, <a href="/search/astro-ph?searchtype=author&query=Corongiu%2C+A">A. Corongiu</a>, <a href="/search/astro-ph?searchtype=author&query=Egron%2C+E">E. Egron</a>, <a href="/search/astro-ph?searchtype=author&query=Iacolina%2C+N">N. Iacolina</a>, <a href="/search/astro-ph?searchtype=author&query=Pellizzoni%2C+A">A. Pellizzoni</a>, <a href="/search/astro-ph?searchtype=author&query=Pilia%2C+M">M. Pilia</a>, <a href="/search/astro-ph?searchtype=author&query=Trois%2C+A">A. Trois</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="1608.01839v1-abstract-short" style="display: inline;"> A background of nanohertz gravitational waves from supermassive black hole binaries could soon be detected by pulsar timing arrays, which measure the times-of-arrival of radio pulses from millisecond pulsars with very high precision. The European Pulsar Timing Array uses five large European radio telescopes to monitor high-precision millisecond pulsars, imposing in this way strong constraints on a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.01839v1-abstract-full').style.display = 'inline'; document.getElementById('1608.01839v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.01839v1-abstract-full" style="display: none;"> A background of nanohertz gravitational waves from supermassive black hole binaries could soon be detected by pulsar timing arrays, which measure the times-of-arrival of radio pulses from millisecond pulsars with very high precision. The European Pulsar Timing Array uses five large European radio telescopes to monitor high-precision millisecond pulsars, imposing in this way strong constraints on a gravitational wave background. To achieve the necessary precision needed to detect gravitational waves, the Large European Array for Pulsars (LEAP) performs simultaneous observations of pulsars with all five telescopes, which allows us to coherently add the radio pulses, maximize the signal-to-noise of pulsar signals and increase the precision of times-of-arrival. We report on the progress made and results obtained by the LEAP collaboration, and in particular on the addition of the Sardinia Radio Telescope to the LEAP observations during its scientific validation phase. In addition, we discuss how LEAP can be used to monitor strong-gravity systems such as double neutron star systems and impose strong constraints on post-keplerian parameters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.01839v1-abstract-full').style.display = 'none'; document.getElementById('1608.01839v1-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 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">7 pages, 4 figures, Proceedings of the 14th Marcel Grossmann Meeting on General Relativity (MG 14), Rome, 2015</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.00129">arXiv:1604.00129</a> <span> [<a href="https://arxiv.org/pdf/1604.00129">pdf</a>, <a href="https://arxiv.org/format/1604.00129">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/stw1134">10.1093/mnras/stw1134 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A millisecond pulsar in an extremely wide binary system </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Tauris%2C+T+M">T. M. Tauris</a>, <a href="/search/astro-ph?searchtype=author&query=Wevers%2C+T">T. Wevers</a>, <a href="/search/astro-ph?searchtype=author&query=Jonker%2C+P+G">P. G. Jonker</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Graikou%2C+E">E. Graikou</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Freire%2C+P+C+C">P. C. C. Freire</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</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=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">A. Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+C">C. Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazaridis%2C+K">K. Lazaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A+G">A. G. Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J">J. McKee</a> , et al. (8 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="1604.00129v1-abstract-short" style="display: inline;"> We report on 22 yrs of radio timing observations of the millisecond pulsar J1024$-$0719 by the telescopes participating in the European Pulsar Timing Array (EPTA). These observations reveal a significant second derivative of the pulsar spin frequency and confirm the discrepancy between the parallax and Shklovskii distances that has been reported earlier. We also present optical astrometry, photome… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.00129v1-abstract-full').style.display = 'inline'; document.getElementById('1604.00129v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.00129v1-abstract-full" style="display: none;"> We report on 22 yrs of radio timing observations of the millisecond pulsar J1024$-$0719 by the telescopes participating in the European Pulsar Timing Array (EPTA). These observations reveal a significant second derivative of the pulsar spin frequency and confirm the discrepancy between the parallax and Shklovskii distances that has been reported earlier. We also present optical astrometry, photometry and spectroscopy of 2MASS J10243869$-$0719190. We find that it is a low-metallicity main-sequence star (K7V spectral type, $\mathrm{[M/H]}=-1.0$, $T_\mathrm{eff}=4050\pm50$ K) and that its position, proper motion and distance are consistent with those of PSR J1024$-$0719. We conclude that PSR J1024$-$0719 and 2MASS J10243869$-$0719190 form a common proper motion pair and are gravitationally bound. The gravitational interaction between the main-sequence star and the pulsar accounts for the spin frequency derivatives, which in turn resolves the distance discrepancy. Our observations suggest that the pulsar and main-sequence star are in an extremely wide ($P_\mathrm{b}>200$ yr) orbit. Combining the radial velocity of the companion and proper motion of the pulsar, we find that the binary system has a high spatial velocity of $384\pm45$ km s$^{-1}$ with respect to the local standard of rest and has a Galactic orbit consistent with halo objects. Since the observed main-sequence companion star cannot have recycled the pulsar to millisecond spin periods, an exotic formation scenario is required. We demonstrate that this extremely wide-orbit binary could have evolved from a triple system that underwent an asymmetric supernova explosion, though find that significant fine-tuning during the explosion is required. Finally, we discuss the implications of the long period orbit on the timing stability of PSR J1024$-$0719 in light of its inclusion in pulsar timing arrays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.00129v1-abstract-full').style.display = 'none'; document.getElementById('1604.00129v1-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 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">16 pages, 12 figures, 2 tables, submitted 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/1602.08511">arXiv:1602.08511</a> <span> [<a href="https://arxiv.org/pdf/1602.08511">pdf</a>, <a href="https://arxiv.org/ps/1602.08511">ps</a>, <a href="https://arxiv.org/format/1602.08511">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/stw483">10.1093/mnras/stw483 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> High-precision timing of 42 millisecond pulsars with the European Pulsar Timing Array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</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=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</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=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Os%C5%82owski%2C+S">S. Os艂owski</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</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=Brem%2C+P">P. Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Gair%2C+J+R">J. R. Gair</a>, <a href="/search/astro-ph?searchtype=author&query=Graikou%2C+E">E. Graikou</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">A. Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+C">C. Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lassus%2C+A">A. Lassus</a>, <a href="/search/astro-ph?searchtype=author&query=Lazaridis%2C+K">K. Lazaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a> , et al. (18 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="1602.08511v1-abstract-short" style="display: inline;"> We report on the high-precision timing of 42 radio millisecond pulsars (MSPs) observed by the European Pulsar Timing Array (EPTA). This EPTA Data Release 1.0 extends up to mid-2014 and baselines range from 7-18 years. It forms the basis for the stochastic gravitational-wave background, anisotropic background, and continuous-wave limits recently presented by the EPTA elsewhere. The Bayesian timing… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08511v1-abstract-full').style.display = 'inline'; document.getElementById('1602.08511v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.08511v1-abstract-full" style="display: none;"> We report on the high-precision timing of 42 radio millisecond pulsars (MSPs) observed by the European Pulsar Timing Array (EPTA). This EPTA Data Release 1.0 extends up to mid-2014 and baselines range from 7-18 years. It forms the basis for the stochastic gravitational-wave background, anisotropic background, and continuous-wave limits recently presented by the EPTA elsewhere. The Bayesian timing analysis performed with TempoNest yields the detection of several new parameters: seven parallaxes, nine proper motions and, in the case of six binary pulsars, an apparent change of the semi-major axis. We find the NE2001 Galactic electron density model to be a better match to our parallax distances (after correction from the Lutz-Kelker bias) than the M2 and M3 models by Schnitzeler (2012). However, we measure an average uncertainty of 80\% (fractional) for NE2001, three times larger than what is typically assumed in the literature. We revisit the transverse velocity distribution for a set of 19 isolated and 57 binary MSPs and find no statistical difference between these two populations. We detect Shapiro delay in the timing residuals of PSRs J1600$-$3053 and J1918$-$0642, implying pulsar and companion masses $m_p=1.22_{-0.35}^{+0.5} \text{M}_{\odot}$, $m_c = 0.21_{-0.04}^{+0.06} \text{M}_{\odot }$ and $m_p=1.25_{-0.4}^{+0.6} \text{M}_{\odot}$, $m_c = 0.23_{-0.05}^{+0.07} \text{M}_{\odot }$, respectively. Finally, we use the measurement of the orbital period derivative to set a stringent constraint on the distance to PSRs J1012$+$5307 and J1909$-$3744, and set limits on the longitude of ascending node through the search of the annual-orbital parallax for PSRs J1600$-$3053 and J1909$-$3744. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08511v1-abstract-full').style.display = 'none'; document.getElementById('1602.08511v1-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 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">42 pages, 11 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/1602.05570">arXiv:1602.05570</a> <span> [<a href="https://arxiv.org/pdf/1602.05570">pdf</a>, <a href="https://arxiv.org/format/1602.05570">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> <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/10.1093/mnras/stw395">10.1093/mnras/stw395 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> From Spin Noise to Systematics: Stochastic Processes in the First International Pulsar Timing Array Data Release </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Shannon%2C+R+M">R. M. Shannon</a>, <a href="/search/astro-ph?searchtype=author&query=Coles%2C+W+A">W. A. Coles</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">R. van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Ellis%2C+J+A">J. A. Ellis</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=Manchester%2C+R+N">R. N. Manchester</a>, <a href="/search/astro-ph?searchtype=author&query=Arzoumanian%2C+Z">Z. Arzoumanian</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</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=Bhat%2C+N+D+R">N. D. R. Bhat</a>, <a href="/search/astro-ph?searchtype=author&query=Brem%2C+P">P. Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Burke-Spolaor%2C+S">S. Burke-Spolaor</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D">D. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J+M">J. M. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Dai%2C+S">S. Dai</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P">P. Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Dolch%2C+T">T. Dolch</a>, <a href="/search/astro-ph?searchtype=author&query=Ferdman%2C+R+D">R. D. Ferdman</a>, <a href="/search/astro-ph?searchtype=author&query=Fonseca%2C+E">E. Fonseca</a> , et al. (58 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="1602.05570v1-abstract-short" style="display: inline;"> We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model selection to determine the optimal description of the stochastic signals present in each pulsar. In addition to spin-noise and dispersion-measure (DM) variations, these models can include timing noise unique to a single… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.05570v1-abstract-full').style.display = 'inline'; document.getElementById('1602.05570v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.05570v1-abstract-full" style="display: none;"> We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model selection to determine the optimal description of the stochastic signals present in each pulsar. In addition to spin-noise and dispersion-measure (DM) variations, these models can include timing noise unique to a single observing system, or frequency band. We show the improved radio-frequency coverage and presence of overlapping data from different observing systems in the IPTA data set enables us to separate both system and band-dependent effects with much greater efficacy than in the individual PTA data sets. For example, we show that PSR J1643$-$1224 has, in addition to DM variations, significant band-dependent noise that is coherent between PTAs which we interpret as coming from time-variable scattering or refraction in the ionised interstellar medium. Failing to model these different contributions appropriately can dramatically alter the astrophysical interpretation of the stochastic signals observed in the residuals. In some cases, the spectral exponent of the spin noise signal can vary from 1.6 to 4 depending upon the model, which has direct implications for the long-term sensitivity of the pulsar to a stochastic gravitational-wave (GW) background. By using a more appropriate model, however, we can greatly improve a pulsar's sensitivity to GWs. For example, including system and band-dependent signals in the PSR J0437$-$4715 data set improves the upper limit on a fiducial GW background by $\sim 60\%$ compared to a model that includes DM variations and spin-noise only. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.05570v1-abstract-full').style.display = 'none'; document.getElementById('1602.05570v1-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 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">29 pages. 16 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/1602.03640">arXiv:1602.03640</a> <span> [<a href="https://arxiv.org/pdf/1602.03640">pdf</a>, <a href="https://arxiv.org/ps/1602.03640">ps</a>, <a href="https://arxiv.org/format/1602.03640">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/stw347">10.1093/mnras/stw347 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The International Pulsar Timing Array: First Data Release </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Hobbs%2C+G">G. Hobbs</a>, <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">R. van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P+B">P. B. Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+J+-">J. -B. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</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=Keith%2C+M+J">M. J. Keith</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=Arzoumanian%2C+Z">Z. Arzoumanian</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</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=Bhat%2C+N+D+R">N. D. R. Bhat</a>, <a href="/search/astro-ph?searchtype=author&query=Brazier%2C+A">A. Brazier</a>, <a href="/search/astro-ph?searchtype=author&query=Brem%2C+P">P. Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Burke-Spolaor%2C+S">S. Burke-Spolaor</a>, <a href="/search/astro-ph?searchtype=author&query=Chamberlin%2C+S+J">S. J. Chamberlin</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Christy%2C+B">B. Christy</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J+M">J. M. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Dai%2C+S">S. Dai</a> , et al. (67 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="1602.03640v1-abstract-short" style="display: inline;"> The highly stable spin of neutron stars can be exploited for a variety of (astro-)physical investigations. In particular arrays of pulsars with rotational periods of the order of milliseconds can be used to detect correlated signals such as those caused by gravitational waves. Three such "Pulsar Timing Arrays" (PTAs) have been set up around the world over the past decades and collectively form the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.03640v1-abstract-full').style.display = 'inline'; document.getElementById('1602.03640v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.03640v1-abstract-full" style="display: none;"> The highly stable spin of neutron stars can be exploited for a variety of (astro-)physical investigations. In particular arrays of pulsars with rotational periods of the order of milliseconds can be used to detect correlated signals such as those caused by gravitational waves. Three such "Pulsar Timing Arrays" (PTAs) have been set up around the world over the past decades and collectively form the "International" PTA (IPTA). In this paper, we describe the first joint analysis of the data from the three regional PTAs, i.e. of the first IPTA data set. We describe the available PTA data, the approach presently followed for its combination and suggest improvements for future PTA research. Particular attention is paid to subtle details (such as underestimation of measurement uncertainty and long-period noise) that have often been ignored but which become important in this unprecedentedly large and inhomogeneous data set. We identify and describe in detail several factors that complicate IPTA research and provide recommendations for future pulsar timing efforts. The first IPTA data release presented here (and available online) is used to demonstrate the IPTA's potential of improving upon gravitational-wave limits placed by individual PTAs by a factor of ~2 and provides a 2-sigma limit on the dimensionless amplitude of a stochastic GWB of 1.7x10^{-15} at a frequency of 1 yr^{-1}. This is 1.7 times less constraining than the limit placed by (Shannon et al. 2015), due mostly to the more recent, high-quality data they used. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.03640v1-abstract-full').style.display = 'none'; document.getElementById('1602.03640v1-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 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">25 pages, 6 tables, 5 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/1511.06597">arXiv:1511.06597</a> <span> [<a href="https://arxiv.org/pdf/1511.06597">pdf</a>, <a href="https://arxiv.org/format/1511.06597">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/stv2755">10.1093/mnras/stv2755 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> LEAP: the large European array for pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">C. G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=McKee%2C+J">J. McKee</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">M. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">S. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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="1511.06597v1-abstract-short" style="display: inline;"> The Large European Array for Pulsars (LEAP) is an experiment that harvests the collective power of Europe's largest radio telescopes in order to increase the sensitivity of high-precision pulsar timing. As part of the ongoing effort of the European Pulsar Timing Array (EPTA), LEAP aims to go beyond the sensitivity threshold needed to deliver the first direct detection of gravitational waves. The f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.06597v1-abstract-full').style.display = 'inline'; document.getElementById('1511.06597v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1511.06597v1-abstract-full" style="display: none;"> The Large European Array for Pulsars (LEAP) is an experiment that harvests the collective power of Europe's largest radio telescopes in order to increase the sensitivity of high-precision pulsar timing. As part of the ongoing effort of the European Pulsar Timing Array (EPTA), LEAP aims to go beyond the sensitivity threshold needed to deliver the first direct detection of gravitational waves. The five telescopes presently included in LEAP are: the Effelsberg telescope, the Lovell telescope at Jodrell Bank, the Nan\c cay radio telescope, the Sardinia Radio Telescope and the Westerbork Synthesis Radio Telescope. Dual polarization, Nyquist-sampled time-series of the incoming radio waves are recorded and processed offline to form the coherent sum, resulting in a tied-array telescope with an effective aperture equivalent to a 195-m diameter circular dish. All observations are performed using a bandwidth of 128 MHz centered at a frequency of 1396 MHz. In this paper, we present the design of the LEAP experiment, the instrumentation, the storage and transfer of data, and the processing hardware and software. In particular, we present the software pipeline that was designed to process the Nyquist-sampled time-series, measure the phase and time delays between each individual telescope and a reference telescope and apply these delays to form the tied-array coherent addition. The pipeline includes polarization calibration and interference mitigation. We also present the first results from LEAP and demonstrate the resulting increase in sensitivity, which leads to an improvement in the pulse arrival times. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1511.06597v1-abstract-full').style.display = 'none'; document.getElementById('1511.06597v1-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 November, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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, 12 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/1510.09194">arXiv:1510.09194</a> <span> [<a href="https://arxiv.org/pdf/1510.09194">pdf</a>, <a href="https://arxiv.org/format/1510.09194">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="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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/stw179">10.1093/mnras/stw179 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The noise properties of 42 millisecond pulsars from the European Pulsar Timing Array and their impact on gravitational wave searches </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. N. Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</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=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Possenti%2C+A">A. Possenti</a>, <a href="/search/astro-ph?searchtype=author&query=Tiburzi%2C+C">C. Tiburzi</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Os%C5%82owski%2C+S">S. Os艂owski</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</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=Brem%2C+P">P. Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Gair%2C+J+R">J. R. Gair</a>, <a href="/search/astro-ph?searchtype=author&query=Graikou%2C+E">E. Graikou</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Lassus%2C+A">A. Lassus</a> , et al. (14 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="1510.09194v3-abstract-short" style="display: inline;"> The sensitivity of Pulsar Timing Arrays to gravitational waves depends on the noise present in the individual pulsar timing data. Noise may be either intrinsic or extrinsic to the pulsar. Intrinsic sources of noise will include rotational instabilities, for example. Extrinsic sources of noise include contributions from physical processes which are not sufficiently well modelled, for example, dispe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.09194v3-abstract-full').style.display = 'inline'; document.getElementById('1510.09194v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1510.09194v3-abstract-full" style="display: none;"> The sensitivity of Pulsar Timing Arrays to gravitational waves depends on the noise present in the individual pulsar timing data. Noise may be either intrinsic or extrinsic to the pulsar. Intrinsic sources of noise will include rotational instabilities, for example. Extrinsic sources of noise include contributions from physical processes which are not sufficiently well modelled, for example, dispersion and scattering effects, analysis errors and instrumental instabilities. We present the results from a noise analysis for 42 millisecond pulsars (MSPs) observed with the European Pulsar Timing Array. For characterising the low-frequency, stochastic and achromatic noise component, or "timing noise", we employ two methods, based on Bayesian and frequentist statistics. For 25 MSPs, we achieve statistically significant measurements of their timing noise parameters and find that the two methods give consistent results. For the remaining 17 MSPs, we place upper limits on the timing noise amplitude at the 95% confidence level. We additionally place an upper limit on the contribution to the pulsar noise budget from errors in the reference terrestrial time standards (below 1%), and we find evidence for a noise component which is present only in the data of one of the four used telescopes. Finally, we estimate that the timing noise of individual pulsars reduces the sensitivity of this data set to an isotropic, stochastic GW background by a factor of >9.1 and by a factor of >2.3 for continuous GWs from resolvable, inspiralling supermassive black-hole binaries with circular orbits. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1510.09194v3-abstract-full').style.display = 'none'; document.getElementById('1510.09194v3-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 January, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 October, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">Accepted for publication by the Monthly Notices of the Royal Astronomical Society</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.05446">arXiv:1509.05446</a> <span> [<a href="https://arxiv.org/pdf/1509.05446">pdf</a>, <a href="https://arxiv.org/format/1509.05446">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/10.1088/1742-6596/716/1/012014">10.1088/1742-6596/716/1/012014 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single-Source Gravitational Wave Limits from the J1713+0747 24-hr Global Campaign </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dolch%2C+T">T. Dolch</a>, <a href="/search/astro-ph?searchtype=author&query=Ellis%2C+J+A">J. A. Ellis</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J+M">J. M. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Lam%2C+M+T">M. T. Lam</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C">C. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+B">B. Bhattacharyya</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=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Crowter%2C+K">K. Crowter</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P+B">P. B. Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G">G. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Jenet%2C+F+A">F. A. Jenet</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+G">G. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+C">C. Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Keith%2C+M">M. Keith</a>, <a href="/search/astro-ph?searchtype=author&query=Kondratiev%2C+V+I">V. I. Kondratiev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. J. W. Lazio</a>, <a href="/search/astro-ph?searchtype=author&query=Lorimer%2C+D+R">D. R. Lorimer</a>, <a href="/search/astro-ph?searchtype=author&query=Madison%2C+D+R">D. R. Madison</a>, <a href="/search/astro-ph?searchtype=author&query=McLaughlin%2C+M+A">M. A. McLaughlin</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="1509.05446v2-abstract-short" style="display: inline;"> Dense, continuous pulsar timing observations over a 24-hr period provide a method for probing intermediate gravitational wave (GW) frequencies from 10 microhertz to 20 millihertz. The European Pulsar Timing Array (EPTA), the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), the Parkes Pulsar Timing Array (PPTA), and the combined International Pulsar Timing Array (IPTA) all u… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.05446v2-abstract-full').style.display = 'inline'; document.getElementById('1509.05446v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.05446v2-abstract-full" style="display: none;"> Dense, continuous pulsar timing observations over a 24-hr period provide a method for probing intermediate gravitational wave (GW) frequencies from 10 microhertz to 20 millihertz. The European Pulsar Timing Array (EPTA), the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), the Parkes Pulsar Timing Array (PPTA), and the combined International Pulsar Timing Array (IPTA) all use millisecond pulsar observations to detect or constrain GWs typically at nanohertz frequencies. In the case of the IPTA's nine-telescope 24-Hour Global Campaign on millisecond pulsar J1713+0747, GW limits in the intermediate frequency regime can be produced. The negligible change in dispersion measure during the observation minimizes red noise in the timing residuals, constraining any contributions from GWs due to individual sources. At 10$^{-5}$Hz, the 95% upper limit on strain is 10$^{-11}$ for GW sources in the pulsar's direction. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.05446v2-abstract-full').style.display = 'none'; document.getElementById('1509.05446v2-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 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">4 pages, 2 figures, published in the proceedings of Amaldi 11</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Physics: Conference Series 716 (2016) 012014 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1509.02165">arXiv:1509.02165</a> <span> [<a href="https://arxiv.org/pdf/1509.02165">pdf</a>, <a href="https://arxiv.org/format/1509.02165">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="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1093/mnras/stv2092">10.1093/mnras/stv2092 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> European Pulsar Timing Array Limits on Continuous Gravitational Waves from Individual Supermassive Black Hole Binaries </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">Stanislav Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Petiteau%2C+A">Antoine Petiteau</a>, <a href="/search/astro-ph?searchtype=author&query=Sesana%2C+A">Alberto Sesana</a>, <a href="/search/astro-ph?searchtype=author&query=Brem%2C+P">Patrick Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Rosado%2C+P+A">Pablo A. Rosado</a>, <a href="/search/astro-ph?searchtype=author&query=Taylor%2C+S+R">Stephen R. Taylor</a>, <a href="/search/astro-ph?searchtype=author&query=Lassus%2C+A">Antoine Lassus</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">Jason W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">Cees G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">Marta Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. Nicolas Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">David J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">Ismael Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">Gregory Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Gair%2C+J+R">Jonathan R. Gair</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">Lucas Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">Gemma H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">Ramesh Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">Michael Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">Patrick Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">Lindley Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">Kuo Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Mingarelli%2C+C+M+F">Chiara M. F. Mingarelli</a>, <a href="/search/astro-ph?searchtype=author&query=Oslowski%2C+S">Stefan Oslowski</a> , et al. (11 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="1509.02165v2-abstract-short" style="display: inline;"> We have searched for continuous gravitational wave (CGW) signals produced by individually resolvable, circular supermassive black hole binaries (SMBHBs) in the latest EPTA dataset, which consists of ultra-precise timing data on 41 millisecond pulsars. We develop frequentist and Bayesian detection algorithms to search both for monochromatic and frequency-evolving systems. None of the adopted algori… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02165v2-abstract-full').style.display = 'inline'; document.getElementById('1509.02165v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1509.02165v2-abstract-full" style="display: none;"> We have searched for continuous gravitational wave (CGW) signals produced by individually resolvable, circular supermassive black hole binaries (SMBHBs) in the latest EPTA dataset, which consists of ultra-precise timing data on 41 millisecond pulsars. We develop frequentist and Bayesian detection algorithms to search both for monochromatic and frequency-evolving systems. None of the adopted algorithms show evidence for the presence of such a CGW signal, indicating that the data are best described by pulsar and radiometer noise only. Depending on the adopted detection algorithm, the 95\% upper limit on the sky-averaged strain amplitude lies in the range $6\times 10^{-15}<A<1.5\times10^{-14}$ at $5{\rm nHz}<f<7{\rm nHz}$. This limit varies by a factor of five, depending on the assumed source position, and the most constraining limit is achieved towards the positions of the most sensitive pulsars in the timing array. The most robust upper limit -- obtained via a full Bayesian analysis searching simultaneously over the signal and pulsar noise on the subset of ours six best pulsars -- is $A\approx10^{-14}$. These limits, the most stringent to date at $f<10{\rm nHz}$, exclude the presence of sub-centiparsec binaries with chirp mass $\cal{M}_c>10^9$M$_\odot$ out to a distance of about 25Mpc, and with $\cal{M}_c>10^{10}$M$_\odot$ out to a distance of about 1Gpc ($z\approx0.2$). We show that state-of-the-art SMBHB population models predict $<1\%$ probability of detecting a CGW with the current EPTA dataset, consistent with the reported non-detection. We stress, however, that PTA limits on individual CGW have improved by almost an order of magnitude in the last five years. The continuing advances in pulsar timing data acquisition and analysis techniques will allow for strong astrophysical constraints on the population of nearby SMBHBs in the coming years. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1509.02165v2-abstract-full').style.display = 'none'; document.getElementById('1509.02165v2-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 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 September, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">16 pages, 11 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/1506.08817">arXiv:1506.08817</a> <span> [<a href="https://arxiv.org/pdf/1506.08817">pdf</a>, <a href="https://arxiv.org/format/1506.08817">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="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/10.1103/PhysRevLett.115.041101">10.1103/PhysRevLett.115.041101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Limits on anisotropy in the nanohertz stochastic gravitational-wave background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Taylor%2C+S+R">S. R. Taylor</a>, <a href="/search/astro-ph?searchtype=author&query=Mingarelli%2C+C+M+F">C. M. F. Mingarelli</a>, <a href="/search/astro-ph?searchtype=author&query=Gair%2C+J+R">J. R. Gair</a>, <a href="/search/astro-ph?searchtype=author&query=Sesana%2C+A">A. Sesana</a>, <a href="/search/astro-ph?searchtype=author&query=Theureau%2C+G">G. Theureau</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">S. Babak</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=Brem%2C+P">P. Brem</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=Champion%2C+D+J">D. J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">L. Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lassus%2C+A">A. Lassus</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Os%C5%82owski%2C+S">S. Os艂owski</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Petiteau%2C+A">A. Petiteau</a> , et al. (10 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="1506.08817v1-abstract-short" style="display: inline;"> The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing analyses sub-optimal. We present the first constraints on the angular distribution of a nanohertz stochastic GWB from circular, inspiral-driven SMBHBs using the $2015$ European Pulsar Timing Array data [Desvignes et al. (in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.08817v1-abstract-full').style.display = 'inline'; document.getElementById('1506.08817v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1506.08817v1-abstract-full" style="display: none;"> The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing analyses sub-optimal. We present the first constraints on the angular distribution of a nanohertz stochastic GWB from circular, inspiral-driven SMBHBs using the $2015$ European Pulsar Timing Array data [Desvignes et al. (in prep.)]. Our analysis of the GWB in the $\sim 2 - 90$ nHz band shows consistency with isotropy, with the strain amplitude in $l>0$ spherical harmonic multipoles $\lesssim 40\%$ of the monopole value. We expect that these more general techniques will become standard tools to probe the angular distribution of source populations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1506.08817v1-abstract-full').style.display = 'none'; document.getElementById('1506.08817v1-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 June, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">6 pages, 2 figures, 1 table. Accepted for publication in Physical Review 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/1504.03692">arXiv:1504.03692</a> <span> [<a href="https://arxiv.org/pdf/1504.03692">pdf</a>, <a href="https://arxiv.org/format/1504.03692">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="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/stv1538">10.1093/mnras/stv1538 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> European Pulsar Timing Array Limits On An Isotropic Stochastic Gravitational-Wave Background </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">Lindley Lentati</a>, <a href="/search/astro-ph?searchtype=author&query=Taylor%2C+S+R">Stephen R. Taylor</a>, <a href="/search/astro-ph?searchtype=author&query=Mingarelli%2C+C+M+F">Chiara M. F. Mingarelli</a>, <a href="/search/astro-ph?searchtype=author&query=Sesana%2C+A">Alberto Sesana</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S+A">Sotiris A. Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Vecchio%2C+A">Alberto Vecchio</a>, <a href="/search/astro-ph?searchtype=author&query=Caballero%2C+R+N">R. Nicolas Caballero</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">Rutger van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Babak%2C+S">Stanislav Babak</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">Cees G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Brem%2C+P">Patrick Brem</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">Marta Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Champion%2C+D+J">David J. Champion</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">Ismael Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">Gregory Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Gair%2C+J+R">Jonathan R. Gair</a>, <a href="/search/astro-ph?searchtype=author&query=Guillemot%2C+L">Lucas Guillemot</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">Jason W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">Gemma H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">Ramesh Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">Michael Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lassus%2C+A">Antoine Lassus</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">Patrick Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">Kuo Liu</a> , et al. (11 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="1504.03692v3-abstract-short" style="display: inline;"> We present new limits on an isotropic stochastic gravitational-wave background (GWB) using a six pulsar dataset spanning 18 yr of observations from the 2015 European Pulsar Timing Array data release. Performing a Bayesian analysis, we fit simultaneously for the intrinsic noise parameters for each pulsar, along with common correlated signals including clock, and Solar System ephemeris errors, obtai… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.03692v3-abstract-full').style.display = 'inline'; document.getElementById('1504.03692v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1504.03692v3-abstract-full" style="display: none;"> We present new limits on an isotropic stochastic gravitational-wave background (GWB) using a six pulsar dataset spanning 18 yr of observations from the 2015 European Pulsar Timing Array data release. Performing a Bayesian analysis, we fit simultaneously for the intrinsic noise parameters for each pulsar, along with common correlated signals including clock, and Solar System ephemeris errors, obtaining a robust 95$\%$ upper limit on the dimensionless strain amplitude $A$ of the background of $A<3.0\times 10^{-15}$ at a reference frequency of $1\mathrm{yr^{-1}}$ and a spectral index of $13/3$, corresponding to a background from inspiralling super-massive black hole binaries, constraining the GW energy density to $惟_\mathrm{gw}(f)h^2 < 1.1\times10^{-9}$ at 2.8 nHz. We also present limits on the correlated power spectrum at a series of discrete frequencies, and show that our sensitivity to a fiducial isotropic GWB is highest at a frequency of $\sim 5\times10^{-9}$~Hz. Finally we discuss the implications of our analysis for the astrophysics of supermassive black hole binaries, and present 95$\%$ upper limits on the string tension, $G渭/c^2$, characterising a background produced by a cosmic string network for a set of possible scenarios, and for a stochastic relic GWB. For a Nambu-Goto field theory cosmic string network, we set a limit $G渭/c^2<1.3\times10^{-7}$, identical to that set by the {\it Planck} Collaboration, when combining {\it Planck} and high-$\ell$ Cosmic Microwave Background data from other experiments. For a stochastic relic background we set a limit of $惟^\mathrm{relic}_\mathrm{gw}(f)h^2<1.2 \times10^{-9}$, a factor of 9 improvement over the most stringent limits previously set by a pulsar timing array. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1504.03692v3-abstract-full').style.display = 'none'; document.getElementById('1504.03692v3-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, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 April, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">24 pages, 5 tables, 17 figures</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 2015 453 (3): 2576-2598 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1502.06785">arXiv:1502.06785</a> <span> [<a href="https://arxiv.org/pdf/1502.06785">pdf</a>, <a href="https://arxiv.org/ps/1502.06785">ps</a>, <a href="https://arxiv.org/format/1502.06785">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/stv397">10.1093/mnras/stv397 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Single pulse and profile variability study of PSR J1022+1001 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M+B">M. B. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</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="1502.06785v1-abstract-short" style="display: inline;"> Millisecond pulsars (MSPs) are known as highly stable celestial clocks. Nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. In this paper, we present a case study on the pulse profile variability of PSR J1022+1001. We have detected approximately 14,000 sub-pulses (components of single pulses) in… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.06785v1-abstract-full').style.display = 'inline'; document.getElementById('1502.06785v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1502.06785v1-abstract-full" style="display: none;"> Millisecond pulsars (MSPs) are known as highly stable celestial clocks. Nevertheless, recent studies have revealed the unstable nature of their integrated pulse profiles, which may limit the achievable pulsar timing precision. In this paper, we present a case study on the pulse profile variability of PSR J1022+1001. We have detected approximately 14,000 sub-pulses (components of single pulses) in 35-hr long observations, mostly located at the trailing component of the integrated profile. Their flux densities and fractional polarisation suggest that they represent the bright end of the energy distribution in ordinary emission mode and are not giant pulses. The occurrence of sub-pulses from the leading and trailing components of the integrated profile is shown to be correlated. For sub-pulses from the latter, a preferred pulse width of approximately 0.25 ms has been found. Using simultaneous observations from the Effelsberg 100-m telescope and the Westerbork Synthesis Radio Telescope, we have found that the integrated profile varies on a timescale of a few tens of minutes. We show that improper polarisation calibration and diffractive scintillation cannot be the sole reason for the observed instability. In addition, we demonstrate that timing residuals generated from averages of the detected sub-pulses are dominated by phase jitter, and place an upper limit of ~700 ns for jitter noise based on continuous 1-min integrations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1502.06785v1-abstract-full').style.display = 'none'; document.getElementById('1502.06785v1-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> 24 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">13 pages, 20 figures, 3 tables, 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/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/1408.1694">arXiv:1408.1694</a> <span> [<a href="https://arxiv.org/pdf/1408.1694">pdf</a>, <a href="https://arxiv.org/format/1408.1694">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/10.1088/0004-637X/794/1/21">10.1088/0004-637X/794/1/21 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A 24-Hour Global Campaign To Assess Precision Timing of the Millisecond Pulsar J1713+0747 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dolch%2C+T">T. Dolch</a>, <a href="/search/astro-ph?searchtype=author&query=Lam%2C+M+T">M. T. Lam</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J+M">J. M. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C">C. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Bhattacharyya%2C+B">B. Bhattacharyya</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=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Crowter%2C+K">K. Crowter</a>, <a href="/search/astro-ph?searchtype=author&query=Demorest%2C+P+B">P. B. Demorest</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Jenet%2C+F+A">F. A. Jenet</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+G">G. Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+C">C. Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Keith%2C+M">M. Keith</a>, <a href="/search/astro-ph?searchtype=author&query=Kondratiev%2C+V+I">V. I. Kondratiev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazarus%2C+P">P. Lazarus</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. J. W. Lazio</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=McLaughlin%2C+M+A">M. A. McLaughlin</a>, <a href="/search/astro-ph?searchtype=author&query=Roy%2C+J">J. Roy</a>, <a href="/search/astro-ph?searchtype=author&query=Shannon%2C+R+M">R. M. Shannon</a> , et al. (18 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="1408.1694v2-abstract-short" style="display: inline;"> The radio millisecond pulsar J1713+0747 is regarded as one of the highest-precision clocks in the sky, and is regularly timed for the purpose of detecting gravitational waves. The International Pulsar Timing Array collaboration undertook a 24-hour global observation of PSR J1713+0747 in an effort to better quantify sources of timing noise in this pulsar, particularly on intermediate (1 - 24 hr) ti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1408.1694v2-abstract-full').style.display = 'inline'; document.getElementById('1408.1694v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1408.1694v2-abstract-full" style="display: none;"> The radio millisecond pulsar J1713+0747 is regarded as one of the highest-precision clocks in the sky, and is regularly timed for the purpose of detecting gravitational waves. The International Pulsar Timing Array collaboration undertook a 24-hour global observation of PSR J1713+0747 in an effort to better quantify sources of timing noise in this pulsar, particularly on intermediate (1 - 24 hr) timescales. We observed the pulsar continuously over 24 hr with the Arecibo, Effelsberg, GMRT, Green Bank, LOFAR, Lovell, Nancay, Parkes, and WSRT radio telescopes. The combined pulse times-of-arrival presented here provide an estimate of what sources of timing noise, excluding DM variations, would be present as compared to an idealized root-N improvement in timing precision, where N is the number of pulses analyzed. In the case of this particular pulsar, we find that intrinsic pulse phase jitter dominates arrival time precision when the S/N of single pulses exceeds unity, as measured using the eight telescopes that observed at L-band/1.4 GHz. We present first results of specific phenomena probed on the unusually long timescale (for a single continuous observing session) of tens of hours, in particular interstellar scintillation, and discuss the degree to which scintillation and profile evolution affect precision timing. This paper presents the data set as a basis for future, deeper studies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1408.1694v2-abstract-full').style.display = 'none'; document.getElementById('1408.1694v2-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 December, 2014; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 August, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">Published in the 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 794, 21 (2014) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1404.2084">arXiv:1404.2084</a> <span> [<a href="https://arxiv.org/pdf/1404.2084">pdf</a>, <a href="https://arxiv.org/ps/1404.2084">ps</a>, <a href="https://arxiv.org/format/1404.2084">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/stu664">10.1093/mnras/stu664 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Model-based asymptotically optimal dispersion measure correction for pulsar timing </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</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=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+K">K. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Perrodin%2C+D">D. Perrodin</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">R. van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Lentati%2C+L">L. Lentati</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="1404.2084v1-abstract-short" style="display: inline;"> In order to reach the sensitivity required to detect gravitational waves, pulsar timing array experiments need to mitigate as much noise as possible in timing data. A dominant amount of noise is likely due to variations in the dispersion measure. To correct for such variations, we develop a statistical method inspired by the maximum likelihood estimator and optimal filtering. Our method consists o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.2084v1-abstract-full').style.display = 'inline'; document.getElementById('1404.2084v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1404.2084v1-abstract-full" style="display: none;"> In order to reach the sensitivity required to detect gravitational waves, pulsar timing array experiments need to mitigate as much noise as possible in timing data. A dominant amount of noise is likely due to variations in the dispersion measure. To correct for such variations, we develop a statistical method inspired by the maximum likelihood estimator and optimal filtering. Our method consists of two major steps. First, the spectral index and amplitude of dispersion measure variations are measured via a time-domain spectral analysis. Second, the linear optimal filter is constructed based on the model parameters found in the first step, and is used to extract the dispersion measure variation waveforms. Compared to current existing methods, this method has better time resolution for the study of short timescale dispersion variations, and generally produces smaller errors in waveform estimations. This method can process irregularly sampled data without any interpolation because of its time-domain nature. Furthermore, it offers the possibility to interpolate or extrapolate the waveform estimation to regions where no data is available. Examples using simulated data sets are included for demonstration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1404.2084v1-abstract-full').style.display = 'none'; document.getElementById('1404.2084v1-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 April, 2014; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">15 pages, 15 figures, submitted 15th Sept. 2013, accepted 2nd April 2014 by MNRAS. MNRAS, 2014</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1204.4321">arXiv:1204.4321</a> <span> [<a href="https://arxiv.org/pdf/1204.4321">pdf</a>, <a href="https://arxiv.org/ps/1204.4321">ps</a>, <a href="https://arxiv.org/format/1204.4321">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="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/10.1111/j.1365-2966.2012.21070.x">10.1111/j.1365-2966.2012.21070.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The optimal schedule for pulsar timing array observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</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=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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="1204.4321v1-abstract-short" style="display: inline;"> In order to maximize the sensitivity of pulsar timing arrays to a stochastic gravitational wave background, we present computational techniques to optimize observing schedules. The techniques are applicable to both single and multi-telescope experiments. The observing schedule is optimized for each telescope by adjusting the observing time allocated to each pulsar while keeping the total amount of… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.4321v1-abstract-full').style.display = 'inline'; document.getElementById('1204.4321v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1204.4321v1-abstract-full" style="display: none;"> In order to maximize the sensitivity of pulsar timing arrays to a stochastic gravitational wave background, we present computational techniques to optimize observing schedules. The techniques are applicable to both single and multi-telescope experiments. The observing schedule is optimized for each telescope by adjusting the observing time allocated to each pulsar while keeping the total amount of observing time constant. The optimized schedule depends on the timing noise characteristics of each individual pulsar as well as the performance of instrumentation. Several examples are given to illustrate the effects of different types of noise. A method to select the most suitable pulsars to be included in a pulsar timing array project is also presented. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1204.4321v1-abstract-full').style.display = 'none'; document.getElementById('1204.4321v1-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 April, 2012; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2012. </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">16 pages, 6 figures, 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/1103.0576">arXiv:1103.0576</a> <span> [<a href="https://arxiv.org/pdf/1103.0576">pdf</a>, <a href="https://arxiv.org/ps/1103.0576">ps</a>, <a href="https://arxiv.org/format/1103.0576">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="Instrumentation and Methods for Astrophysics">astro-ph.IM</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/10.1111/j.1365-2966.2011.18613.x">10.1111/j.1365-2966.2011.18613.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Placing limits on the stochastic gravitational-wave background using European Pulsar Timing Array data </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">R. van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Levin%2C+Y">Y. Levin</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Lazaridis%2C+K">K. Lazaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+M+K+B+W">M. Kramer B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M+B">M. B. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A+G">A. G. Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=Ferdman%2C+R+D">R. D. Ferdman</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">A. Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Theureau%2C+G">G. Theureau</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amico%2C+N">N. D'Amico</a>, <a href="/search/astro-ph?searchtype=author&query=Possenti%2C+A">A. Possenti</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">M. Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Corongiu%2C+A">A. Corongiu</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">J. W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</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="1103.0576v1-abstract-short" style="display: inline;"> Direct detection of low-frequency gravitational waves ($10^{-9} - 10^{-8}$ Hz) is the main goal of pulsar timing array (PTA) projects. One of the main targets for the PTAs is to measure the stochastic background of gravitational waves (GWB) whose characteristic strain is expected to approximately follow a power-law of the form $h_c(f)=A (f/\hbox{yr}^{-1})^伪$, where $f$ is the gravitational-wave fr… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.0576v1-abstract-full').style.display = 'inline'; document.getElementById('1103.0576v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1103.0576v1-abstract-full" style="display: none;"> Direct detection of low-frequency gravitational waves ($10^{-9} - 10^{-8}$ Hz) is the main goal of pulsar timing array (PTA) projects. One of the main targets for the PTAs is to measure the stochastic background of gravitational waves (GWB) whose characteristic strain is expected to approximately follow a power-law of the form $h_c(f)=A (f/\hbox{yr}^{-1})^伪$, where $f$ is the gravitational-wave frequency. In this paper we use the current data from the European PTA to determine an upper limit on the GWB amplitude $A$ as a function of the unknown spectral slope $伪$ with a Bayesian algorithm, by modelling the GWB as a random Gaussian process. For the case $伪=-2/3$, which is expected if the GWB is produced by supermassive black-hole binaries, we obtain a 95% confidence upper limit on $A$ of $6\times 10^{-15}$, which is 1.8 times lower than the 95% confidence GWB limit obtained by the Parkes PTA in 2006. Our approach to the data analysis incorporates the multi-telescope nature of the European PTA and thus can serve as a useful template for future intercontinental PTA collaborations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.0576v1-abstract-full').style.display = 'none'; document.getElementById('1103.0576v1-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> 2 March, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2011. </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">14 pages, 8 figures, 3 tables, mnras accepted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1103.0115">arXiv:1103.0115</a> <span> [<a href="https://arxiv.org/pdf/1103.0115">pdf</a>, <a href="https://arxiv.org/ps/1103.0115">ps</a>, <a href="https://arxiv.org/format/1103.0115">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 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/10.1111/j.1365-2966.2011.18622.x">10.1111/j.1365-2966.2011.18622.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gravitational wave astronomy of single sources with a pulsar timing array </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lee%2C+K+J">K. J. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Wex%2C+N">N. Wex</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</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=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">R. Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. 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="1103.0115v1-abstract-short" style="display: inline;"> Abbreviated: We investigate the potential of detecting the gravitational wave from individual binary black hole systems using pulsar timing arrays (PTAs) and calculate the accuracy for determining the GW properties. This is done in a consistent analysis, which at the same time accounts for the measurement of the pulsar distances via the timing parallax. We find that, at low redshift, a PTA is… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.0115v1-abstract-full').style.display = 'inline'; document.getElementById('1103.0115v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1103.0115v1-abstract-full" style="display: none;"> Abbreviated: We investigate the potential of detecting the gravitational wave from individual binary black hole systems using pulsar timing arrays (PTAs) and calculate the accuracy for determining the GW properties. This is done in a consistent analysis, which at the same time accounts for the measurement of the pulsar distances via the timing parallax. We find that, at low redshift, a PTA is able to detect the nano-Hertz GW from super massive black hole binary systems with masses of $\sim10^8 - 10^{10}\,M_{\sun}$ less than $\sim10^5$\,years before the final merger, and those with less than $\sim10^3 - 10^4$ years before merger may allow us to detect the evolution of binaries. We derive an analytical expression to describe the accuracy of a pulsar distance measurement via timing parallax. We consider five years of bi-weekly observations at a precision of 15\,ns for close-by ($\sim 0.5 - 1$\,kpc) pulsars. Timing twenty pulsars would allow us to detect a GW source with an amplitude larger than $5\times 10^{-17}$. We calculate the corresponding GW and binary orbital parameters and their measurement precision. The accuracy of measuring the binary orbital inclination angle, the sky position, and the GW frequency are calculated as functions of the GW amplitude. We note that the "pulsar term", which is commonly regarded as noise, is essential for obtaining an accurate measurement for the GW source location. We also show that utilizing the information encoded in the GW signal passing the Earth also increases the accuracy of pulsar distance measurements. If the gravitational wave is strong enough, one can achieve sub-parsec distance measurements for nearby pulsars with distance less than $\sim 0.5 - 1$\,kpc. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1103.0115v1-abstract-full').style.display = 'none'; document.getElementById('1103.0115v1-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 March, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2011. </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">16 pages, 5 figure,, 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/1102.5646">arXiv:1102.5646</a> <span> [<a href="https://arxiv.org/pdf/1102.5646">pdf</a>, <a href="https://arxiv.org/ps/1102.5646">ps</a>, <a href="https://arxiv.org/format/1102.5646">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> </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/10.1111/j.1365-2966.2011.18610.x">10.1111/j.1365-2966.2011.18610.x <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence for gravitational quadrupole moment variations in the companion of PSR J2051-0827 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lazaridis%2C+K">K. Lazaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Verbiest%2C+J+P+W">J. P. W. Verbiest</a>, <a href="/search/astro-ph?searchtype=author&query=Tauris%2C+T+M">T. M. Tauris</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B+W">B. W. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Wex%2C+N">N. Wex</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">A. Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">I. Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">G. Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">G. H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M+B">M. B. Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Theureau%2C+G">G. Theureau</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=Smits%2C+R">R. 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="1102.5646v1-abstract-short" style="display: inline;"> We have conducted radio timing observations of the eclipsing millisecond binary pulsar J2051-0827 with the European Pulsar Timing Array network of telescopes and the Parkes radio telescope, spanning over 13 years. The increased data span allows significant measurements of the orbital eccentricity, e = (6.2 {\pm} 1.3) {\times} 10^{-5} and composite proper motion, 渭_t = 7.3 {\pm} 0.4 mas/yr. Our tim… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.5646v1-abstract-full').style.display = 'inline'; document.getElementById('1102.5646v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1102.5646v1-abstract-full" style="display: none;"> We have conducted radio timing observations of the eclipsing millisecond binary pulsar J2051-0827 with the European Pulsar Timing Array network of telescopes and the Parkes radio telescope, spanning over 13 years. The increased data span allows significant measurements of the orbital eccentricity, e = (6.2 {\pm} 1.3) {\times} 10^{-5} and composite proper motion, 渭_t = 7.3 {\pm} 0.4 mas/yr. Our timing observations have revealed secular variations of the projected semi-major axis of the pulsar orbit which are much more extreme than those previously published; and of the orbital period of the system. Investigation of the physical mechanisms producing such variations confirm that the variations of the semi-major axis are most probably caused by classical spin-orbit coupling in the binary system, while the variations in orbital period are most likely caused by tidal dissipation leading to changes in the gravitational quadrupole moment of the companion. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1102.5646v1-abstract-full').style.display = 'none'; document.getElementById('1102.5646v1-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 February, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2011. </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, 7 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, Volume 414, Issue 4, pp. 3134-3144 (2011) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1101.5971">arXiv:1101.5971</a> <span> [<a href="https://arxiv.org/pdf/1101.5971">pdf</a>, <a href="https://arxiv.org/ps/1101.5971">ps</a>, <a href="https://arxiv.org/format/1101.5971">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="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/10.1051/0004-6361/201016141">10.1051/0004-6361/201016141 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Prospects for accurate distance measurements of pulsars with the SKA: enabling fundamental physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Tingay%2C+S+J">S. J. Tingay</a>, <a href="/search/astro-ph?searchtype=author&query=Wex%2C+N">N. Wex</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B">B. Stappers</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="1101.5971v3-abstract-short" style="display: inline;"> Parallax measurements of pulsars allow for accurate measurements of the interstellar electron density and contribute to accurate tests of general relativity using binary systems. The Square Kilometre Array (SKA) will be an ideal instrument for measuring the parallax of pulsars, because it has a very high sensitivity, as well as baselines extending up to several thousands of kilometres. We performe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1101.5971v3-abstract-full').style.display = 'inline'; document.getElementById('1101.5971v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1101.5971v3-abstract-full" style="display: none;"> Parallax measurements of pulsars allow for accurate measurements of the interstellar electron density and contribute to accurate tests of general relativity using binary systems. The Square Kilometre Array (SKA) will be an ideal instrument for measuring the parallax of pulsars, because it has a very high sensitivity, as well as baselines extending up to several thousands of kilometres. We performed simulations to estimate the number of pulsars for which the parallax can be measured with the SKA and the distance to which a parallax can be measured. We compare two different methods. The first method measures the parallax directly by utilising the long baselines of the SKA to form high angular resolution images. The second method uses the arrival times of the radio signals of pulsars to fit a transformation between time coordinates in the terrestrial frame and the comoving pulsar frame directly yielding the parallax. We find that with the first method a parallax with an accuracy of 20% or less can be measured up to a maximum distance of 13 kpc, which would include 9,000 pulsars. By timing pulsars with the most stable arrival times for the radio emission, parallaxes can be measured for about 3,600 millisecond pulsars up to a distance of 9 kpc with an accuracy of 20%. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1101.5971v3-abstract-full').style.display = 'none'; document.getElementById('1101.5971v3-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> 17 February, 2011; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 31 January, 2011; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2011. </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, 8 figures, accepted for publication in A&A, table format has been modified, language edited</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1012.3507">arXiv:1012.3507</a> <span> [<a href="https://arxiv.org/pdf/1012.3507">pdf</a>, <a href="https://arxiv.org/ps/1012.3507">ps</a>, <a href="https://arxiv.org/format/1012.3507">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/10.1063/1.3615151">10.1063/1.3615151 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pulsars with the Australian Square Kilometre Array Pathfinder </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Stairs%2C+I+H">I. H. Stairs</a>, <a href="/search/astro-ph?searchtype=author&query=Keith%2C+M+J">M. J. Keith</a>, <a href="/search/astro-ph?searchtype=author&query=Arzoumanian%2C+Z">Z. Arzoumanian</a>, <a href="/search/astro-ph?searchtype=author&query=Becker%2C+W">W. Becker</a>, <a href="/search/astro-ph?searchtype=author&query=Berndsen%2C+A">A. Berndsen</a>, <a href="/search/astro-ph?searchtype=author&query=Bouchard%2C+A">A. Bouchard</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=Burgay%2C+M">M. Burgay</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=Chatterjee%2C+S">S. Chatterjee</a>, <a href="/search/astro-ph?searchtype=author&query=Colegate%2C+T">T. Colegate</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J+M">J. M. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Crawford%2C+F+M">F. M. Crawford</a>, <a href="/search/astro-ph?searchtype=author&query=Dodson%2C+R">R. Dodson</a>, <a href="/search/astro-ph?searchtype=author&query=Freire%2C+P+C+C">P. C. C. Freire</a>, <a href="/search/astro-ph?searchtype=author&query=Hobbs%2C+G+B">G. B. Hobbs</a>, <a href="/search/astro-ph?searchtype=author&query=Hotan%2C+A+W">A. W. Hotan</a>, <a href="/search/astro-ph?searchtype=author&query=Johnston%2C+S">S. Johnston</a>, <a href="/search/astro-ph?searchtype=author&query=Kaspi%2C+V+M">V. M. Kaspi</a>, <a href="/search/astro-ph?searchtype=author&query=Kondratiev%2C+V">V. Kondratiev</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazio%2C+T+J+W">T. J. W. Lazio</a>, <a href="/search/astro-ph?searchtype=author&query=Majid%2C+W">W. Majid</a>, <a href="/search/astro-ph?searchtype=author&query=Manchester%2C+R+N">R. N. Manchester</a>, <a href="/search/astro-ph?searchtype=author&query=Nice%2C+D+J">D. J. Nice</a> , et al. (11 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="1012.3507v1-abstract-short" style="display: inline;"> The Australian Square Kilometre Array Pathfinder (ASKAP) is a 36-element array with a 30-square-degree field of view being built at the proposed SKA site in Western Australia. We are conducting a Design Study for pulsar observations with ASKAP, planning both timing and search observations. We provide an overview of the ASKAP telescope and an update on pulsar-related progress. </span> <span class="abstract-full has-text-grey-dark mathjax" id="1012.3507v1-abstract-full" style="display: none;"> The Australian Square Kilometre Array Pathfinder (ASKAP) is a 36-element array with a 30-square-degree field of view being built at the proposed SKA site in Western Australia. We are conducting a Design Study for pulsar observations with ASKAP, planning both timing and search observations. We provide an overview of the ASKAP telescope and an update on pulsar-related progress. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1012.3507v1-abstract-full').style.display = 'none'; document.getElementById('1012.3507v1-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 December, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2010. </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 proceedings of "Radio Pulsars: An astrophysical key to unlock the secrets of the Universe"</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1003.3405">arXiv:1003.3405</a> <span> [<a href="https://arxiv.org/pdf/1003.3405">pdf</a>, <a href="https://arxiv.org/ps/1003.3405">ps</a>, <a href="https://arxiv.org/format/1003.3405">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/10.1088/0264-9381/27/8/084014">10.1088/0264-9381/27/8/084014 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The European Pulsar Timing Array: current efforts and a LEAP toward the future </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ferdman%2C+R+D">Robert D. Ferdman</a>, <a href="/search/astro-ph?searchtype=author&query=van+Haasteren%2C+R">Rutger van Haasteren</a>, <a href="/search/astro-ph?searchtype=author&query=Bassa%2C+C+G">Cees G. Bassa</a>, <a href="/search/astro-ph?searchtype=author&query=Burgay%2C+M">Marta Burgay</a>, <a href="/search/astro-ph?searchtype=author&query=Cognard%2C+I">Ismael Cognard</a>, <a href="/search/astro-ph?searchtype=author&query=Corongiu%2C+A">Alessandro Corongiu</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amico%2C+N">Nichi D'Amico</a>, <a href="/search/astro-ph?searchtype=author&query=Desvignes%2C+G">Gregory Desvignes</a>, <a href="/search/astro-ph?searchtype=author&query=Hessels%2C+J+W+T">Jason W. T. Hessels</a>, <a href="/search/astro-ph?searchtype=author&query=Janssen%2C+G+H">Gemma H. Janssen</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">Axel Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Jordan%2C+C">Christine Jordan</a>, <a href="/search/astro-ph?searchtype=author&query=Karuppusamy%2C+R">Ramesh Karuppusamy</a>, <a href="/search/astro-ph?searchtype=author&query=Keane%2C+E+F">Evan F. Keane</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">Michael Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Lazaridis%2C+K">Kosmas Lazaridis</a>, <a href="/search/astro-ph?searchtype=author&query=Levin%2C+Y">Yuri Levin</a>, <a href="/search/astro-ph?searchtype=author&query=Lyne%2C+A+G">Andrew G. Lyne</a>, <a href="/search/astro-ph?searchtype=author&query=Pilia%2C+M">Maura Pilia</a>, <a href="/search/astro-ph?searchtype=author&query=Possenti%2C+A">Andrea Possenti</a>, <a href="/search/astro-ph?searchtype=author&query=Purver%2C+M">Mark Purver</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B">Ben Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Sanidas%2C+S">Sotirios Sanidas</a>, <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">Roy Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Theureau%2C+G">Gilles Theureau</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="1003.3405v1-abstract-short" style="display: inline;"> The European Pulsar Timing Array (EPTA) is a multi-institutional, multi-telescope collaboration, with the goal of using high-precision pulsar timing to directly detect gravitational waves. In this article we discuss the EPTA member telescopes, current achieved timing precision, and near-future goals. We report a preliminary upper limit to the amplitude of a gravitational wave background. We also d… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.3405v1-abstract-full').style.display = 'inline'; document.getElementById('1003.3405v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1003.3405v1-abstract-full" style="display: none;"> The European Pulsar Timing Array (EPTA) is a multi-institutional, multi-telescope collaboration, with the goal of using high-precision pulsar timing to directly detect gravitational waves. In this article we discuss the EPTA member telescopes, current achieved timing precision, and near-future goals. We report a preliminary upper limit to the amplitude of a gravitational wave background. We also discuss the Large European Array for Pulsars, in which the five major European telescopes involved in pulsar timing will be combined to provide a coherent array that will give similar sensitivity to the Arecibo radio telescope, and larger sky coverage. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1003.3405v1-abstract-full').style.display = 'none'; document.getElementById('1003.3405v1-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> 17 March, 2010; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2010. </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, 2 figures, 2 tables, Amaldi 8 conference proceedings, accepted for publication by Classical & Quantum Gravity</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Class.Quant.Grav.27:084014,2010 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0908.1689">arXiv:0908.1689</a> <span> [<a href="https://arxiv.org/pdf/0908.1689">pdf</a>, <a href="https://arxiv.org/ps/0908.1689">ps</a>, <a href="https://arxiv.org/format/0908.1689">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/10.1051/0004-6361/200911939">10.1051/0004-6361/200911939 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pulsar science with the Five hundred metre Aperture Spherical Telescope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Lorimer%2C+D+R">D. R. Lorimer</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Manchester%2C+R">R. Manchester</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B">B. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+C+J">C. J. Jin</a>, <a href="/search/astro-ph?searchtype=author&query=Nan%2C+R+D">R. D. Nan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+D">D. Li</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="0908.1689v2-abstract-short" style="display: inline;"> With a collecting area of 70 000 m^2, the Five hundred metre Aperture Spherical Telescope (FAST) will allow for great advances in pulsar astronomy. We have performed simulations to estimate the number of previously unknown pulsars FAST will find with its 19-beam or possibly 100-beam receivers for different survey strategies. With the 19-beam receiver, a total of 5200 previously unknown pulsars c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0908.1689v2-abstract-full').style.display = 'inline'; document.getElementById('0908.1689v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0908.1689v2-abstract-full" style="display: none;"> With a collecting area of 70 000 m^2, the Five hundred metre Aperture Spherical Telescope (FAST) will allow for great advances in pulsar astronomy. We have performed simulations to estimate the number of previously unknown pulsars FAST will find with its 19-beam or possibly 100-beam receivers for different survey strategies. With the 19-beam receiver, a total of 5200 previously unknown pulsars could be discovered in the Galactic plane, including about 460 millisecond pulsars (MSPs). Such a survey would take just over 200 days with eight hours survey time per day. We also estimate that, with about 80 six-hour days, a survey of M31 and M33 could yield 50--100 extra-Galactic pulsars. A 19-beam receiver would produce just under 500 MB of data per second and requires about 9 tera-ops to perform the major part of a real time analysis. We also simulate the logistics of high-precision timing of MSPs with FAST. Timing of the 50 brightest MSPs to a signal-to-noise of 500 would take about 24 hours per epoch. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0908.1689v2-abstract-full').style.display = 'none'; document.getElementById('0908.1689v2-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> 17 August, 2009; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 12 August, 2009; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2009. </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, 10 figures; accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/0811.0211">arXiv:0811.0211</a> <span> [<a href="https://arxiv.org/pdf/0811.0211">pdf</a>, <a href="https://arxiv.org/ps/0811.0211">ps</a>, <a href="https://arxiv.org/format/0811.0211">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-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/10.1051/0004-6361:200810383">10.1051/0004-6361:200810383 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Pulsar searches and timing with the SKA </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Kramer%2C+M">M. Kramer</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B">B. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Lorimer%2C+D+R">D. R. Lorimer</a>, <a href="/search/astro-ph?searchtype=author&query=Cordes%2C+J">J. Cordes</a>, <a href="/search/astro-ph?searchtype=author&query=Faulkner%2C+A">A. Faulkner</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="0811.0211v1-abstract-short" style="display: inline;"> The Square Kilometre Array (SKA) is a planned multi purpose radio telescope with a collecting area approaching 1 million square metres. One of the key science objectives of the SKA is to provide exquisite strong-field tests of gravitational physics by finding and timing pulsars in extreme binary systems such as a pulsar-black hole binary. To find out how three preliminary SKA configurations will… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0811.0211v1-abstract-full').style.display = 'inline'; document.getElementById('0811.0211v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="0811.0211v1-abstract-full" style="display: none;"> The Square Kilometre Array (SKA) is a planned multi purpose radio telescope with a collecting area approaching 1 million square metres. One of the key science objectives of the SKA is to provide exquisite strong-field tests of gravitational physics by finding and timing pulsars in extreme binary systems such as a pulsar-black hole binary. To find out how three preliminary SKA configurations will affect a pulsar survey, we have simulated SKA pulsar surveys for each configuration. We estimate that the total number of normal pulsars the SKA will detect, using only the 1-km core and 30 minutes integration time, is around 14000 normal pulsar and 6000 millisecond pulsars. We describe a simple strategy for follow-up timing observations and find that, depending on the configuration, it would take 1-6 days to obtain a single timing point for 14000 pulsars. Obtaining a single timing point for the high-precision timing projects of the SKA, will take less than 14 hours, 2 days, or 3 days, depending on the configuration. The presence of aperture arrays will be of great benefit here. We also study the computational requirements for beam forming and data analysis for a pulsar survey. Beam forming of the full field of view of the single-pixel feed 15-m dishes using the 1-km core of the SKA requires about 2.2*10^15 operations per second. The corresponding data rate from such a pulsar survey is about 4.7*10^11 bytes per second. The required computational power for a deep real time analysis is estimated to be 1.2*10^16 operations per second. For an aperture array or dishes equipped with phased array feeds, the survey can be performed faster, but the computational requirements and data rates will go up. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('0811.0211v1-abstract-full').style.display = 'none'; document.getElementById('0811.0211v1-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> 2 November, 2008; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2008. </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, 9 figures, accepted for publication in A&A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/astro-ph/0612684">arXiv:astro-ph/0612684</a> <span> [<a href="https://arxiv.org/pdf/astro-ph/0612684">pdf</a>, <a href="https://arxiv.org/ps/astro-ph/0612684">ps</a>, <a href="https://arxiv.org/format/astro-ph/0612684">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics">astro-ph</span> </div> </div> <p class="title is-5 mathjax"> The geometry of PSR B0031-07 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Smits%2C+R">R. Smits</a>, <a href="/search/astro-ph?searchtype=author&query=Mitra%2C+D">D. Mitra</a>, <a href="/search/astro-ph?searchtype=author&query=Stappers%2C+B">B. Stappers</a>, <a href="/search/astro-ph?searchtype=author&query=Kuijpers%2C+J">J. Kuijpers</a>, <a href="/search/astro-ph?searchtype=author&query=Weltevrede%2C+P">P. Weltevrede</a>, <a href="/search/astro-ph?searchtype=author&query=Jessner%2C+A">A. Jessner</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+Y">Y. Gupta</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="astro-ph/0612684v1-abstract-short" style="display: inline;"> Here we present the results from an analysis of a multifrequency simultaneous observation of PSR B0031$-$07. We have constructed a geometrical model, based on an empirical relationship between height and frequency of emission, that reproduces many of the observed characteristics. The model suggests very low emission altitudes for this pulsar of only a few kilometers above the star's surface. </span> <span class="abstract-full has-text-grey-dark mathjax" id="astro-ph/0612684v1-abstract-full" style="display: none;"> Here we present the results from an analysis of a multifrequency simultaneous observation of PSR B0031$-$07. We have constructed a geometrical model, based on an empirical relationship between height and frequency of emission, that reproduces many of the observed characteristics. The model suggests very low emission altitudes for this pulsar of only a few kilometers above the star's surface. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('astro-ph/0612684v1-abstract-full').style.display = 'none'; document.getElementById('astro-ph/0612684v1-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 December, 2006; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2006. </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 the 363. WE-Heraeus Seminar on: Neutron Stars and Pulsars (Posters and contributed talks) Physikzentrum Bad Honnef, Germany, May.14-19, 2006, eds. W.Becker, H.H.Huang, MPE Report 291, pp.161-164</span> </p> </li> </ol> <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">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

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