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class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2501.12440">arXiv:2501.12440</a> <span> [<a href="https://arxiv.org/pdf/2501.12440">pdf</a>, <a href="https://arxiv.org/format/2501.12440">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 Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> Pulse and Polarization Structures in Axion-Converted X-rays from Pulsars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng Li</a>, <a href="/search/astro-ph?searchtype=author&query=Sun%2C+C">Chen Sun</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="2501.12440v1-abstract-short" style="display: inline;"> Neutron stars (NS's) with their strong magnetic fields and hot dense cores could be powerful probes of axions, a classic benchmark of feebly-coupled new particles, through abundant production of axions with the axion-nucleon coupling and subsequent conversion into X-rays due to the axion-photon coupling. In this article, we point out that the pulsation structures in both the intensity and polariza… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.12440v1-abstract-full').style.display = 'inline'; document.getElementById('2501.12440v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2501.12440v1-abstract-full" style="display: none;"> Neutron stars (NS's) with their strong magnetic fields and hot dense cores could be powerful probes of axions, a classic benchmark of feebly-coupled new particles, through abundant production of axions with the axion-nucleon coupling and subsequent conversion into X-rays due to the axion-photon coupling. In this article, we point out that the pulsation structures in both the intensity and polarization of X-rays from NS's could provide us additional information about axions and their couplings. We develop new analytical formalisms of pulsation-polarization structure applicable to a wide range of NS's in the axion scenario and argue that they hold in complicated astrophysical environments. As a case study, we apply our formalism to a representative X-ray Dim Isolated Neutron Star, RX J1856.6-3754, with an unexpected hard X-ray excess which might be axion-induced. We show with an updated fit that the axion explanation is compatible with both the intensity and pulsation data available. Yet the preferred parameter space is close to being excluded by other astrophysical constraints. With an achievable reduction of the uncertainties in the pulsation data, we could potentially draw a definite conclusion on the axion-induced X-rays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2501.12440v1-abstract-full').style.display = 'none'; document.getElementById('2501.12440v1-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> 21 January, 2025; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2025. </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">5+7 pages, 7 figures, comments are welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2412.20842">arXiv:2412.20842</a> <span> [<a href="https://arxiv.org/pdf/2412.20842">pdf</a>, <a href="https://arxiv.org/format/2412.20842">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> <p class="title is-5 mathjax"> Revisiting the flaring activity in early 2015 of BL Lacertae object S5 0716+714 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ouyang%2C+Z">Zhihao Ouyang</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Manganaro%2C+M">Marina Manganaro</a>, <a href="/search/astro-ph?searchtype=author&query=Xie%2C+S">Shangchun Xie</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+J">Jingyu Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+J">Jianzhen Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Xue%2C+R">Rui Xue</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+G">Gege Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+S">Shaohua Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</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="2412.20842v1-abstract-short" style="display: inline;"> In this work, we analyzed multi-wavelength data of the BL Lac object S5 0716+714 to investigate its emission mechanisms during a flaring state observed in early 2015. We examined the temporal behavior and broadband spectral energy distributions (SEDs) during the flare. The size of the $纬$-ray emission region was estimated based on the variability timescale. To explore the multi-wavelength properti… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20842v1-abstract-full').style.display = 'inline'; document.getElementById('2412.20842v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2412.20842v1-abstract-full" style="display: none;"> In this work, we analyzed multi-wavelength data of the BL Lac object S5 0716+714 to investigate its emission mechanisms during a flaring state observed in early 2015. We examined the temporal behavior and broadband spectral energy distributions (SEDs) during the flare. The size of the $纬$-ray emission region was estimated based on the variability timescale. To explore the multi-wavelength properties of S5 0716+714, we employed three one-zone models: the SSC model, the SSC plus EC model, and the SSC plus pp interactions model, to reproduce the SEDs. Our findings indicate that while the SSC model can describe the SEDs, it requires an extreme Doppler factor. In contrast, the SSC plus EC model successfully fits the SEDs under the assumption of weak external photon fields but requires a high Doppler factor. Additionally, the SSC plus interactions model also reproduces the SEDs, with $纬$-ray emission originating from $蟺^{0}$ decay. However, this model leads to a jet power that exceeds the Eddington luminosity, which remains plausible due to the flaring state or the presence of a highly collimated jet. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2412.20842v1-abstract-full').style.display = 'none'; document.getElementById('2412.20842v1-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 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 5 figures, accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.11373">arXiv:2411.11373</a> <span> [<a href="https://arxiv.org/pdf/2411.11373">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad8353">10.3847/1538-4357/ad8353 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Study of Jet Formation Mechanism in Fermi Blazars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xie%2C+S">Shangchun Xie</a>, <a href="/search/astro-ph?searchtype=author&query=Ouyang%2C+Z">Zhihao Ouyang</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+J">Jingyu Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+S">Shaohua Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Y">Yongyun Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Luo%2C+Z">Zhijian Luo</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</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="2411.11373v1-abstract-short" style="display: inline;"> The origin of jet launching mainly comes from two mechanisms: the BZ mechanism and the BP mechanism. However, it is in debate which one is dominating in blazars. In this work, we used a sample of 937 Fermi blazars to study the jet formation mechanism. We studied the correlation between the jet power and the accretion rate, as well as the comparison between jet power estimated by spectral energy di… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11373v1-abstract-full').style.display = 'inline'; document.getElementById('2411.11373v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.11373v1-abstract-full" style="display: none;"> The origin of jet launching mainly comes from two mechanisms: the BZ mechanism and the BP mechanism. However, it is in debate which one is dominating in blazars. In this work, we used a sample of 937 Fermi blazars to study the jet formation mechanism. We studied the correlation between the jet power and the accretion rate, as well as the comparison between jet power estimated by spectral energy distribution (SED) fitting and that estimated by theoretical formula and radio flux density. Our results suggest that there is no correlation between jet power estimated by SED fitting and the accretion rate for BL Lacs, while a positive and weak correlation exists for flat spectrum radio quasars (FSRQs). Meanwhile, to confirm whether the BP and BZ mechanism is sufficient to launch the jet for FSRQs and BL Lacs, we compare the theoretical jet power with that estimated by SED fitting, as well as that by radio emission. We found that the jet power for most of the two subclasses estimated by SED fitting cannot be explained by either the BP or BZ mechanism. While the jet power for most FSRQs estimated by radio flux density can be explained by the BP mechanism, and most BL Lacs can be explained by the BZ mechanism. We also found that FSRQs have higher accretion rates than BL Lacs, implying different accretion disks around their central black holes: FSRQs typically have standard disks, while BL Lacs usually have advection-dominated accretion flow disks. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.11373v1-abstract-full').style.display = 'none'; document.getElementById('2411.11373v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ,2024,976,78 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.01215">arXiv:2411.01215</a> <span> [<a href="https://arxiv.org/pdf/2411.01215">pdf</a>, <a href="https://arxiv.org/format/2411.01215">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> <p class="title is-5 mathjax"> Detection of two TeV gamma-ray outbursts from NGC 1275 by LHAASO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+T+L">T. L. Chen</a> , et al. (254 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="2411.01215v2-abstract-short" style="display: inline;"> The Water Cherenkov Detector Array (WCDA) is one of the components of Large High Altitude Air Shower Observatory (LHAASO) and can monitor any sources over two-thirds of the sky for up to 7 hours per day with >98\% duty cycle. In this work, we report the detection of two outbursts of the Fanaroff-Riley I radio galaxy NGC 1275 that were detected by LHAASO-WCDA between November 2022 and January 2023… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.01215v2-abstract-full').style.display = 'inline'; document.getElementById('2411.01215v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.01215v2-abstract-full" style="display: none;"> The Water Cherenkov Detector Array (WCDA) is one of the components of Large High Altitude Air Shower Observatory (LHAASO) and can monitor any sources over two-thirds of the sky for up to 7 hours per day with >98\% duty cycle. In this work, we report the detection of two outbursts of the Fanaroff-Riley I radio galaxy NGC 1275 that were detected by LHAASO-WCDA between November 2022 and January 2023 with statistical significance of 5.2~$蟽$ and 8.3~$蟽$. The observed spectral energy distribution in the range from 500 GeV to 3 TeV is fitted by a power-law with a best-fit spectral index of $伪=-3.37\pm0.52$ and $-3.35\pm0.29$, respectively. The outburst flux above 0.5~TeV was ($4.55\pm 4.21)\times~10^{-11}~\rm cm^{-2}~s^{-1}$ and ($3.45\pm 1.78)\times~10^{-11}~\rm cm^{-2}~s^{-1}$, corresponding to 60\%, 45\% of Crab Nebula flux. Variation analysis reveals the variability time-scale of days at the TeV energy band. A simple test by one-zone synchrotron self-Compton model reproduces the data in the gamma-ray band well. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.01215v2-abstract-full').style.display = 'none'; document.getElementById('2411.01215v2-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 2 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 8 figures, 3 tables</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.07879">arXiv:2410.07879</a> <span> [<a href="https://arxiv.org/pdf/2410.07879">pdf</a>, <a href="https://arxiv.org/format/2410.07879">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> <p class="title is-5 mathjax"> Jets, accretion and spin in supermassive black holes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Y">Yongyun Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Gu%2C+Q">Qiusheng Gu</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+J">Jianghe Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Yu%2C+X">Xiaoling Yu</a>, <a href="/search/astro-ph?searchtype=author&query=Xiong%2C+D">Dingrong Xiong</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+N">Nan Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+X">Xiaotong Guo</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="2410.07879v1-abstract-short" style="display: inline;"> The theoretical model suggests that relativistic jets of AGN rely on the black hole spin and/or accretion. We study the relationship between jet, accretion, and spin using supermassive black hole samples with reliable spin of black holes. Our results are as follows: (1) There is a weak correlation between radio luminosity and the spin of black hole for our sample, which may imply that the jet of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.07879v1-abstract-full').style.display = 'inline'; document.getElementById('2410.07879v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.07879v1-abstract-full" style="display: none;"> The theoretical model suggests that relativistic jets of AGN rely on the black hole spin and/or accretion. We study the relationship between jet, accretion, and spin using supermassive black hole samples with reliable spin of black holes. Our results are as follows: (1) There is a weak correlation between radio luminosity and the spin of black hole for our sample, which may imply that the jet of the supermassive black hole in our sample depends on the other physical parameters besides black hole spins, such as accretion disk luminosity. (2) The jet power of a supermassive black hole can be explained by the hybrid model with magnetic field of corona. (3) There is a significant correlation between radio-loudness and black hole spin for our sample. These sources with high radio-loudness tend to have high black hole spins. These results provide observational evidence that the black hole spin may explain the bimodal phenomena of radio-loud and radio-quiet AGN. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.07879v1-abstract-full').style.display = 'none'; document.getElementById('2410.07879v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13pages,4figures, accept for publication in RAA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.05372">arXiv:2410.05372</a> <span> [<a href="https://arxiv.org/pdf/2410.05372">pdf</a>, <a href="https://arxiv.org/format/2410.05372">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> </div> </div> <p class="title is-5 mathjax"> Cosmic Reionization On Computers: Biases and Uncertainties in the Measured Mean Free Path at the End Stage of Reionization </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+H">Huanqing Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jiawen Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Avestruz%2C+C">Camille Avestruz</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="2410.05372v2-abstract-short" style="display: inline;"> Recent observations and analyses of absorption in quasar spectra suggest a rapid drop in the mean free path (MFP) at the late stage of reionization at $z\sim6$. We use the Cosmic Reionization on Computers simulation to examine potential biases in observed measurements of the MFP at the late stage of reionization, particularly in the presence of a quasar. We analyze three snapshots surrounding the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05372v2-abstract-full').style.display = 'inline'; document.getElementById('2410.05372v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.05372v2-abstract-full" style="display: none;"> Recent observations and analyses of absorption in quasar spectra suggest a rapid drop in the mean free path (MFP) at the late stage of reionization at $z\sim6$. We use the Cosmic Reionization on Computers simulation to examine potential biases in observed measurements of the MFP at the late stage of reionization, particularly in the presence of a quasar. We analyze three snapshots surrounding the `ankle' point of reionization history, when extended neutral patches of the intergalactic medium disappeared in the simulation box. Specifically, these are $z=6.8$ (true MFP $\approx 0.4$~pMpc), in addition to $z=6.1$ (true MFP $\approx 2$~pMpc) and $z=5.4$ (true MFP $\approx 6$~pMpc). We compare the inferred MFP $位_{\rm mfp}$ from synthetic spectra fits to the true MFP. We find that the mean Lyman continuum (LyC) profile at $z=6.8$ changes significantly with quasar lifetime $t_Q$. We attribute this sensitivity to $t_Q$ to a combination of extended neutral IGM patches and the prevalence of small-scale dense clumps. Consequently, the inferred MFP can be biased by a factor of few depending on $t_Q$. On the other hand, for the $z=6.1$ and $z=5.4$ snapshots, the mean LyC profile shows minimal sensitivity to variation in $t_Q\gtrsim 1$ Myr. The inferred MFP in these two cases is accurate to the $\lesssim 30\%$ level. Our results highlight how modeling systematics can affect the inferred MFP, particularly in the regime of small true MFP ($\lesssim 0.5$ pMpc). We also discuss the potential of this regime to provide a testing ground for constraining quasar lifetimes from LyC profiles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.05372v2-abstract-full').style.display = 'none'; document.getElementById('2410.05372v2-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 9 figures, comments welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.04425">arXiv:2410.04425</a> <span> [<a href="https://arxiv.org/pdf/2410.04425">pdf</a>, <a href="https://arxiv.org/format/2410.04425">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> <p class="title is-5 mathjax"> LHAASO detection of very-high-energy gamma-ray emission surrounding PSR J0248+6021 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2410.04425v2-abstract-short" style="display: inline;"> We report the detection of an extended very-high-energy (VHE) gamma-ray source coincident with the location of middle-aged (62.4~\rm kyr) pulsar PSR J0248+6021, by using the LHAASO-WCDA data of live 796 days and LHAASO-KM2A data of live 1216 days. A significant excess of \gray induced showers is observed both by WCDA in energy bands of 1-25~\rm TeV and KM2A in energy bands of $>$ 25~\rm TeV with 7… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04425v2-abstract-full').style.display = 'inline'; document.getElementById('2410.04425v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.04425v2-abstract-full" style="display: none;"> We report the detection of an extended very-high-energy (VHE) gamma-ray source coincident with the location of middle-aged (62.4~\rm kyr) pulsar PSR J0248+6021, by using the LHAASO-WCDA data of live 796 days and LHAASO-KM2A data of live 1216 days. A significant excess of \gray induced showers is observed both by WCDA in energy bands of 1-25~\rm TeV and KM2A in energy bands of $>$ 25~\rm TeV with 7.3 $蟽$ and 13.5 $蟽$, respectively. The best-fit position derived through WCDA data is R.A. = 42.06$^\circ \pm$ 0.12$^\circ$ and Dec. = 60.24$^\circ \pm $ 0.13$^\circ$ with an extension of 0.69$^\circ\pm$0.15$^\circ$ and that of the KM2A data is R.A.= 42.29$^\circ \pm $ 0.13$^\circ$ and Dec. = 60.38$^\circ \pm$ 0.07$^\circ$ with an extension of 0.37$^\circ\pm$0.07$^\circ$. No clear extended multiwavelength counterpart of this LHAASO source has been found from the radio band to the GeV band. The most plausible explanation of the VHE \gray emission is the inverse Compton process of highly relativistic electrons and positrons injected by the pulsar. These electrons/positrons are hypothesized to be either confined within the pulsar wind nebula or to have already escaped into the interstellar medium, forming a pulsar halo. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.04425v2-abstract-full').style.display = 'none'; document.getElementById('2410.04425v2-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> 3 December, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 10 figures, Accepted by Sci. China-Phys. Mech. Astron</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.10616">arXiv:2409.10616</a> <span> [<a href="https://arxiv.org/pdf/2409.10616">pdf</a>, <a href="https://arxiv.org/format/2409.10616">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 Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> </div> <p class="title is-5 mathjax"> The Juno Mission as a Probe of Long-Range New Physics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Singh%2C+P">Praniti Singh</a>, <a href="/search/astro-ph?searchtype=author&query=Yan%2C+S">Shi Yan</a>, <a href="/search/astro-ph?searchtype=author&query=Allali%2C+I+J">Itamar J. Allali</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng 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="2409.10616v1-abstract-short" style="display: inline;"> Orbits of celestial objects, especially the geocentric and heliocentric ones, have been well explored to constrain new long-range forces beyond the Standard Model (SM), often referred to as fifth forces. In this paper, for the first time, we apply the motion of a spacecraft around Jupiter to probe fifth forces that don't violate the equivalence principle. The spacecraft is the Juno orbiter, and te… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10616v1-abstract-full').style.display = 'inline'; document.getElementById('2409.10616v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.10616v1-abstract-full" style="display: none;"> Orbits of celestial objects, especially the geocentric and heliocentric ones, have been well explored to constrain new long-range forces beyond the Standard Model (SM), often referred to as fifth forces. In this paper, for the first time, we apply the motion of a spacecraft around Jupiter to probe fifth forces that don't violate the equivalence principle. The spacecraft is the Juno orbiter, and ten of its early orbits already allow a precise determination of the Jovian gravitational field. We use the shift in the precession angle as a proxy to test non-gravitational interactions between Juno and Jupiter. Requiring that the contribution from the fifth force does not exceed the uncertainty of the precession shift inferred from data, we find that a new parameter space with the mass of the fifth-force mediator around $10^{-14}$ eV is excluded at 95% C.L. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.10616v1-abstract-full').style.display = 'none'; document.getElementById('2409.10616v1-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 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 4 figures, plus appendices</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2406.08698">arXiv:2406.08698</a> <span> [<a href="https://arxiv.org/pdf/2406.08698">pdf</a>, <a href="https://arxiv.org/format/2406.08698">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="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Constraints on Ultra Heavy Dark Matter Properties from Dwarf Spheroidal Galaxies with LHAASO Observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2406.08698v1-abstract-short" style="display: inline;"> In this work we try to search for signals generated by ultra-heavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible gamma-ray by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter which have low fluxes… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08698v1-abstract-full').style.display = 'inline'; document.getElementById('2406.08698v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2406.08698v1-abstract-full" style="display: none;"> In this work we try to search for signals generated by ultra-heavy dark matter at the Large High Altitude Air Shower Observatory (LHAASO) data. We look for possible gamma-ray by dark matter annihilation or decay from 16 dwarf spheroidal galaxies in the field of view of LHAASO. Dwarf spheroidal galaxies are among the most promising targets for indirect detection of dark matter which have low fluxes of astrophysical $纬$-ray background while large amount of dark matter. By analyzing more than 700 days observational data at LHAASO, no significant dark matter signal from 1 TeV to 1 EeV is detected. Accordingly we derive the most stringent constraints on the ultra-heavy dark matter annihilation cross-section up to EeV. The constraints on the lifetime of dark matter in decay mode are also derived. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2406.08698v1-abstract-full').style.display = 'none'; document.getElementById('2406.08698v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 12 figures, accepted by PRL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.15156">arXiv:2405.15156</a> <span> [<a href="https://arxiv.org/pdf/2405.15156">pdf</a>, <a href="https://arxiv.org/format/2405.15156">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> <p class="title is-5 mathjax"> Spectral fittings of warm coronal radiation with high seed photon temperature: apparent low-temperature and flat soft excess in AGNs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Tang%2C+Z">Ze-Yuan Tang</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+J">Jun-Jie Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jun-Hui Fan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.15156v1-abstract-short" style="display: inline;"> A warm corona has been widely proposed to explain the soft X-ray excess (SE) above the 2--10 keV power law extrapolation in AGNs. In actual spectral fittings, the warm coronal seed photon temperature ($T_{\rm s}$) is usually assumed to be far away from the soft X-ray, but $kT_{\rm s}$ can reach close to 0.1 keV in standard accretion disc model. In this study, we used Monte Carlo simulations to obt… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.15156v1-abstract-full').style.display = 'inline'; document.getElementById('2405.15156v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.15156v1-abstract-full" style="display: none;"> A warm corona has been widely proposed to explain the soft X-ray excess (SE) above the 2--10 keV power law extrapolation in AGNs. In actual spectral fittings, the warm coronal seed photon temperature ($T_{\rm s}$) is usually assumed to be far away from the soft X-ray, but $kT_{\rm s}$ can reach close to 0.1 keV in standard accretion disc model. In this study, we used Monte Carlo simulations to obtain radiation spectra from a slab-like warm corona and fitted the spectra using the spherical-geometry-based routine \textsc{thcomp} or a thermal component. Our findings reveal that high $T_{\rm s}$ can influence the fitting results. A moderately high $kT_{\rm s}$ (around 0.03 keV) can result in an apparent low-temperature and flat SE, while an extremely high $kT_{\rm s}$ (around 0.07 keV) can even produce an unobserved blackbody-like SE. Our conclusions indicate that, for spectral fittings of the warm coronal radiation (SE in AGNs), $kT_{\rm s}$ should be treated as a free parameter with an upper limit, and an accurate coronal geometry is necessary when $kT_{\rm s}>0.01$ keV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.15156v1-abstract-full').style.display = 'none'; document.getElementById('2405.15156v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in RAA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.11826">arXiv:2405.11826</a> <span> [<a href="https://arxiv.org/pdf/2405.11826">pdf</a>, <a href="https://arxiv.org/format/2405.11826">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 Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Data quality control system and long-term performance monitor of the LHAASO-KM2A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bian%2C+W">W. Bian</a>, <a href="/search/astro-ph?searchtype=author&query=Bukevich%2C+A+V">A. V. Bukevich</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+H+X">H. X. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S">S. Chen</a> , et al. (263 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="2405.11826v3-abstract-short" style="display: inline;"> The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic ray and gamma-ray showers. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. To… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.11826v3-abstract-full').style.display = 'inline'; document.getElementById('2405.11826v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.11826v3-abstract-full" style="display: none;"> The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic ray and gamma-ray showers. This information is used for physical analysis in gamma-ray astronomy and cosmic ray physics. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. According to the observation of the Crab Nebula at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be $-0.003^{\circ} \pm 0.005^{\circ}$ and $0.001^{\circ} \pm 0.006^{\circ}$ in the R.A. and Dec directions, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.11826v3-abstract-full').style.display = 'none'; document.getElementById('2405.11826v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 June, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 9 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.07691">arXiv:2405.07691</a> <span> [<a href="https://arxiv.org/pdf/2405.07691">pdf</a>, <a href="https://arxiv.org/format/2405.07691">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> <p class="title is-5 mathjax"> Discovery of Very-high-energy Gamma-ray Emissions from the Low Luminosity AGN NGC 4278 by LHAASO </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2405.07691v1-abstract-short" style="display: inline;"> The first source catalog of Large High Altitude Air Shower Observatory reported the detection of a very-high-energy gamma ray source, 1LHAASO J1219+2915. In this paper a further detailed study of the spectral and temporal behavior of this point-like source have been carried. The best-fit position of the TeV source ($\rm{RA}=185.05^{\circ}\pm0.04^{\circ}$, $\rm{Dec}=29.25^{\circ}\pm0.03^{\circ}$) i… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.07691v1-abstract-full').style.display = 'inline'; document.getElementById('2405.07691v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.07691v1-abstract-full" style="display: none;"> The first source catalog of Large High Altitude Air Shower Observatory reported the detection of a very-high-energy gamma ray source, 1LHAASO J1219+2915. In this paper a further detailed study of the spectral and temporal behavior of this point-like source have been carried. The best-fit position of the TeV source ($\rm{RA}=185.05^{\circ}\pm0.04^{\circ}$, $\rm{Dec}=29.25^{\circ}\pm0.03^{\circ}$) is compatible with NGC 4278 within $\sim0.03$ degree. Variation analysis shows an indication of the variability at a few months level in the TeV band, which is consistent with low frequency observations. Based on these observations, we report the detection of TeV $纬$-ray emissions from this low-luminosity AGN NGC 4278. The observations by LHAASO-WCDA during active period has a significance level of 8.8\,$蟽$ with best-fit photon spectral index $\varGamma=2.56\pm0.14$ and a flux $f_{1-10\,\rm{TeV}}=(7.0\pm1.1_{\rm{sta}}\pm0.35_{\rm{syst}})\times10^{-13}\,\rm{photons\,cm^{-2}\,s^{-1}}$, or approximately $5\%$ of the Crab Nebula. The discovery of VHE from NGC 4278 indicates that the compact, weak radio jet can efficiently accelerate particles and emit TeV photons. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.07691v1-abstract-full').style.display = 'none'; document.getElementById('2405.07691v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 5 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.07028">arXiv:2405.07028</a> <span> [<a href="https://arxiv.org/pdf/2405.07028">pdf</a>, <a href="https://arxiv.org/format/2405.07028">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> <p class="title is-5 mathjax"> Systematic Search and Study of Short-Timescale Flare Structures in BL Lac object Gamma-ray Emission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yu%2C+J">Jinjie Yu</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+N">Nan Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Tang%2C+Y">Yunyong Tang</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+J">Jin Cao</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.07028v1-abstract-short" style="display: inline;"> We present here the first systematic search of short timescale $纬$-ray flares from 29 high Galactic latitude BL Lac objects over 14 years of Fermi Large Area Telescope data. Using a combined Bayesian Blocks and HOP algorithm, we identified seven high-quality orbital timescale flare segments from three sources and quantified 24 short-timescale flare structures. We then performed a comprehensive ana… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.07028v1-abstract-full').style.display = 'inline'; document.getElementById('2405.07028v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.07028v1-abstract-full" style="display: none;"> We present here the first systematic search of short timescale $纬$-ray flares from 29 high Galactic latitude BL Lac objects over 14 years of Fermi Large Area Telescope data. Using a combined Bayesian Blocks and HOP algorithm, we identified seven high-quality orbital timescale flare segments from three sources and quantified 24 short-timescale flare structures. We then performed a comprehensive analysis of flare symmetry, power spectral density (PSD) of variability, and flux-photon index relation. The main results are as follows: (1) The flare symmetry parameter $A$ shows a "U-shaped" distribution. Short timescale flares are symmetric while long timescale flares are asymmetric. The number of fast-rise slow-decay and slow-rise fast-decay type flares are equal. No correlation is found between $A$ and peak/integral flux. No parameter evolution is seen between consecutive flares either. The observations support a scenario where longer timescale flares originate from superposition of short, symmetric sub-hour flares. (2) PSD from yearly to hourly timescales is modeled using the CARMA process. At lower frequencies, the PSD follows the typical broken power-law form. The high-frequency region of the PSD exhibits a continuous power-law shape, indicating that $纬$-ray variability originates from a single physical process across all probed timescales. (3) The flux-photon index distribution shows a pattern of "harder-when-brighter" or "softer-when-brighter," but becomes flat above a certain critical flux, with $螕$ $\approx$ 2. This behavior cannot be simply explained by a two-component or blazar sequence model, and we speculate it may be related to complex interplay between electron acceleration and cooling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.07028v1-abstract-full').style.display = 'none'; document.getElementById('2405.07028v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 5 figures, 2 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/2405.04270">arXiv:2405.04270</a> <span> [<a href="https://arxiv.org/pdf/2405.04270">pdf</a>, <a href="https://arxiv.org/format/2405.04270">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> <p class="title is-5 mathjax"> Very Long Baseline Array Observations of Parsec-scale Radio Emission in Dual Active Galactic Nuclei </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xu%2C+W">Wancheng Xu</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+L">Lang Cui</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+X">Xiang Liu</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+T">Tao An</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+H">Hongmin Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Jiang%2C+P">Pengfei Jiang</a>, <a href="/search/astro-ph?searchtype=author&query=Ho%2C+L+C">Luis C. Ho</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+N">Ning Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+X">Xiaolong Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Shen%2C+Y">Yuling Shen</a>, <a href="/search/astro-ph?searchtype=author&query=Tan%2C+G">Guiping Tan</a>, <a href="/search/astro-ph?searchtype=author&query=Han%2C+Z">Zhenhua Han</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+M">Ming Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.04270v1-abstract-short" style="display: inline;"> It is believed that dual active galactic nuclei (dual AGN) will form during galaxies merge. Studying dual-AGN emission can provide valuable insights into galaxy merging and evolution. To investigate parsec-scale radio emission properties, we observed eight radio components of four selected dual-AGN systems using the Very Long Baseline Array (VLBA) at 5 GHz in multiple-phase-center mode. Among them… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.04270v1-abstract-full').style.display = 'inline'; document.getElementById('2405.04270v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.04270v1-abstract-full" style="display: none;"> It is believed that dual active galactic nuclei (dual AGN) will form during galaxies merge. Studying dual-AGN emission can provide valuable insights into galaxy merging and evolution. To investigate parsec-scale radio emission properties, we observed eight radio components of four selected dual-AGN systems using the Very Long Baseline Array (VLBA) at 5 GHz in multiple-phase-center mode. Among them, two compact radio components, labeled J0051+0020B and J2300-0005A, were detected clearly on parsec scales for the first time. However, the radio emission of the other six components was resolved out in the high-resolution images. We provided the values or upper limits of the brightness temperature and radio emission power, and analyzed the emission origins in detail for each target. Based on their physical properties reported in this work and in the literature, we suggest the radio emission in J0051+0020B and J2300-0005A originates primarily from compact jets, while the other six sources show more complex emission mechanisms. In addition, our VLBA observations suggest the systematic X-ray deficit in our dual-AGN sample is likely attributed to the tidally induced effect and possible viewing angle effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.04270v1-abstract-full').style.display = 'none'; document.getElementById('2405.04270v1-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 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 4 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.00100">arXiv:2405.00100</a> <span> [<a href="https://arxiv.org/pdf/2405.00100">pdf</a>, <a href="https://arxiv.org/format/2405.00100">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> </div> </div> <p class="title is-5 mathjax"> Cosmic Reionization on Computers: The Evolution of Ionizing Background and Mean Free Path </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jiawen Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+H">Huanqing Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Avestruz%2C+C">Camille Avestruz</a>, <a href="/search/astro-ph?searchtype=author&query=Khadir%2C+A">Affan Khadir</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.00100v1-abstract-short" style="display: inline;"> Observations of the end stages of reionization indicate that at $z\approx 5-6$, the ionizing background is not uniform and the mean free path (MFP) changes drastically. As MFP is closely related to the distribution of Lyman Limit Systems and Damped Lyman-alpha Systems (LLSs and DLAs, or ionizing photon "sinks"), it is important to understand them. In this study, we utilize the CROC simulations, wh… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00100v1-abstract-full').style.display = 'inline'; document.getElementById('2405.00100v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.00100v1-abstract-full" style="display: none;"> Observations of the end stages of reionization indicate that at $z\approx 5-6$, the ionizing background is not uniform and the mean free path (MFP) changes drastically. As MFP is closely related to the distribution of Lyman Limit Systems and Damped Lyman-alpha Systems (LLSs and DLAs, or ionizing photon "sinks"), it is important to understand them. In this study, we utilize the CROC simulations, which have both sufficient spatial resolution to resolve galaxy formation and LLSs alongside a fully coupled radiative transfer to simulate the reionization processes. In our analysis, we connect the evolution of the ionizing background and the MFP. We analyze two CROC boxes with distinct reionization histories and find that the distribution of ionizing background in both simulations display significant skewness that deviate from log-normal. Further, the ionizing background in late reionization box still displays significant fluctuations ($\sim 40\%$) at $z\approx5$. We also measure the MFP along sightlines that start 0.15 pMpc away from the center of potential quasar hosting halos. The evolution of the MFP measured from these sightlines exhibits a break that coincides with when all the neutral islands disappear in the reionization history of each box (the `ankle' of the reionization history of the box). In the absence of LLSs, the MFP will be biased high by $\approx 20\%$ at $z\approx 5$. We also compare the MFP measured in random sightlines. We find that at $z\approx 5$ the MFP measured in sightlines that start from massive halos are systematically smaller by $\approx 10\%$ compared with the MFP measured in random sightlines. We attribute this difference to the concentration of dense structures within 1 pMpc from massive halos. Our findings highlight the importance of high fidelity models in the interpretation of observational measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.00100v1-abstract-full').style.display = 'none'; document.getElementById('2405.00100v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 14 figures, comments welcome</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.04801">arXiv:2404.04801</a> <span> [<a href="https://arxiv.org/pdf/2404.04801">pdf</a>, <a href="https://arxiv.org/ps/2404.04801">ps</a>, <a href="https://arxiv.org/format/2404.04801">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s41605-024-00467-8">10.1007/s41605-024-00467-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> LHAASO-KM2A detector simulation using Geant4 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (254 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="2404.04801v1-abstract-short" style="display: inline;"> KM2A is one of the main sub-arrays of LHAASO, working on gamma ray astronomy and cosmic ray physics at energies above 10 TeV. Detector simulation is the important foundation for estimating detector performance and data analysis. It is a big challenge to simulate the KM2A detector in the framework of Geant4 due to the need to track numerous photons from a large number of detector units (>6000) with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04801v1-abstract-full').style.display = 'inline'; document.getElementById('2404.04801v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.04801v1-abstract-full" style="display: none;"> KM2A is one of the main sub-arrays of LHAASO, working on gamma ray astronomy and cosmic ray physics at energies above 10 TeV. Detector simulation is the important foundation for estimating detector performance and data analysis. It is a big challenge to simulate the KM2A detector in the framework of Geant4 due to the need to track numerous photons from a large number of detector units (>6000) with large altitude difference (30 m) and huge coverage (1.3 km^2). In this paper, the design of the KM2A simulation code G4KM2A based on Geant4 is introduced. The process of G4KM2A is optimized mainly in memory consumption to avoid memory overffow. Some simpliffcations are used to signiffcantly speed up the execution of G4KM2A. The running time is reduced by at least 30 times compared to full detector simulation. The particle distributions and the core/angle resolution comparison between simulation and experimental data of the full KM2A array are also presented, which show good agreement. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04801v1-abstract-full').style.display = 'none'; document.getElementById('2404.04801v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.04609">arXiv:2404.04609</a> <span> [<a href="https://arxiv.org/pdf/2404.04609">pdf</a>, <a href="https://arxiv.org/format/2404.04609">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> <p class="title is-5 mathjax"> The particle acceleration study in blazar jet </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+W">Wenxin Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Y">Yutao Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+S">Shaohua Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Fu%2C+L">Liping Fu</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+J">Jianghe Yang</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="2404.04609v1-abstract-short" style="display: inline;"> The particle acceleration of blazar jets is crucial to high-energy astrophysics, yet the acceleration mechanism division in blazar subclasses and the underlying nature of these mechanisms remain elusive. In this work, we utilized the synchrotron spectral information (synchrotron peak frequency, $\log 谓_{\rm sy}$, and corresponding curvature, $b_{\rm sy}$) of 2705 blazars from the literature and st… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04609v1-abstract-full').style.display = 'inline'; document.getElementById('2404.04609v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.04609v1-abstract-full" style="display: none;"> The particle acceleration of blazar jets is crucial to high-energy astrophysics, yet the acceleration mechanism division in blazar subclasses and the underlying nature of these mechanisms remain elusive. In this work, we utilized the synchrotron spectral information (synchrotron peak frequency, $\log 谓_{\rm sy}$, and corresponding curvature, $b_{\rm sy}$) of 2705 blazars from the literature and studied the subject of particle acceleration in blazar jets by analysing the correlation between $\log 谓_{\rm sy}$ and $1/b_{\rm sy}$. Our results suggested that the entire sample follows an energy-dependent probability acceleration (EDPA). Specifically, the low inverse Compton peak sources (LCPs) follow the mechanism that fluctuations of fractional gain acceleration (FFGA), while the high inverse Compton peak sources (HCPs) follow an acceleration mechanism of EDPA. Our results indicated that the separation between LCPs and HCPs results from the electron peak Lorentz factor ($纬_{\rm p}$), and the differentiation should originate from different acceleration mechanisms. Moreover, our study revealed a transition in the acceleration mechanism from FFGA to EDPA around $\log 谓_{\rm sy} \sim 15$ through a detailed analysis of binned-$\log 谓_{\rm sy}$. The mechanism of FFGA dominates the particle acceleration in LCP jets because of stronger jets and the EDPA dominates the particle energy gain in the HCPs due to a more efficient acceleration process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.04609v1-abstract-full').style.display = 'none'; document.getElementById('2404.04609v1-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 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.10010">arXiv:2403.10010</a> <span> [<a href="https://arxiv.org/pdf/2403.10010">pdf</a>, <a href="https://arxiv.org/format/2403.10010">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/10.1103/PhysRevLett.132.131002">10.1103/PhysRevLett.132.131002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=The+LHAASO+Collaboration"> The LHAASO Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu%2C+A">A. Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a> , et al. (256 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="2403.10010v2-abstract-short" style="display: inline;"> We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10010v2-abstract-full').style.display = 'inline'; document.getElementById('2403.10010v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.10010v2-abstract-full" style="display: none;"> We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at $3.67 \pm 0.05 \pm 0.15$ PeV. Below the knee, the spectral index is found to be -$2.7413 \pm 0.0004 \pm 0.0050$, while above the knee, it is -$3.128 \pm 0.005 \pm 0.027$, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -$0.1200 \pm 0.0003 \pm 0.0341$. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.10010v2-abstract-full').style.display = 'none'; document.getElementById('2403.10010v2-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 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 March, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Physical Review Letters 132, 131002 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2403.00078">arXiv:2403.00078</a> <span> [<a href="https://arxiv.org/pdf/2403.00078">pdf</a>, <a href="https://arxiv.org/format/2403.00078">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad0fdf">10.3847/1538-4357/ad0fdf <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Physical Properties of Changing-look Blazars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kang%2C+S">Shi-Ju Kang</a>, <a href="/search/astro-ph?searchtype=author&query=Lyu%2C+B">Bing Lyu</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+Q">Qingwen Wu</a>, <a href="/search/astro-ph?searchtype=author&query=Zheng%2C+Y">Yong-Gang Zheng</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</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="2403.00078v1-abstract-short" style="display: inline;"> Changing-look active galactic nuclei (AGNs) are a special class of AGNs that change their spectral type from type 1 to type 2 or vice versa. In recent years, a number of changing-look blazars (CLBs) were also reported, which transition between flat-spectrum radio quasars and BL Lacs. The physical properties of CLBs are still unclear. Using the $mclust$ R package for Gaussian Mixture Modeling, we p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00078v1-abstract-full').style.display = 'inline'; document.getElementById('2403.00078v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2403.00078v1-abstract-full" style="display: none;"> Changing-look active galactic nuclei (AGNs) are a special class of AGNs that change their spectral type from type 1 to type 2 or vice versa. In recent years, a number of changing-look blazars (CLBs) were also reported, which transition between flat-spectrum radio quasars and BL Lacs. The physical properties of CLBs are still unclear. Using the $mclust$ R package for Gaussian Mixture Modeling, we performed a clustering analysis for a sample of 105 CLBs selected from the literature. Three kinds of analysis found that CLBs lie in between the parameter distributions of FSRQs and BL Lacs: (i) univariate analysis; (ii) bivariate analysis; and (iii) multivariate analysis, carried out with a dimension reduction approach of the physical properties of the three types of blazars. Our results suggest that CLBs belong to a transition type between FSRQs and BL Lacs, which may be regulated by the change of accretion process and may be similar to other changing-look AGNs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2403.00078v1-abstract-full').style.display = 'none'; document.getElementById('2403.00078v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in ApJ. 8 pages, 3 figures, 1 table</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2402.09924">arXiv:2402.09924</a> <span> [<a href="https://arxiv.org/pdf/2402.09924">pdf</a>, <a href="https://arxiv.org/ps/2402.09924">ps</a>, <a href="https://arxiv.org/format/2402.09924">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> <p class="title is-5 mathjax"> Understanding the phenomenological and intrinsic blazar sequence using a simple scaling model </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wan%2C+Z">Zhu-Jian Wan</a>, <a href="/search/astro-ph?searchtype=author&query=Xue%2C+R">Rui Xue</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Z">Ze-Rui Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hu-Bing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jun-Hui Fan</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="2402.09924v1-abstract-short" style="display: inline;"> The blazar sequence, including negative correlations between radiative luminosity $L_{\rm rad}$ and synchrotron peak frequency $谓$, and between Compton dominance $Y$ and $谓$, is widely adopted as a phenomenological description of spectral energy distributions (SEDs) of blazars, although its underlying cause is hotly debated. In particular, these correlations turn positive after correcting Doppler… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09924v1-abstract-full').style.display = 'inline'; document.getElementById('2402.09924v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.09924v1-abstract-full" style="display: none;"> The blazar sequence, including negative correlations between radiative luminosity $L_{\rm rad}$ and synchrotron peak frequency $谓$, and between Compton dominance $Y$ and $谓$, is widely adopted as a phenomenological description of spectral energy distributions (SEDs) of blazars, although its underlying cause is hotly debated. In particular, these correlations turn positive after correcting Doppler boosting effect. In this work, we revisit the phenomenological and intrinsic blazar sequence with three samples, which are historical sample (SEDs are built with historical data), quasi-simultaneous sample (SEDs are built with quasi-simultaneous data) and Doppler factor corrected sample (a sample with available Doppler factors), selected from literature. We find that phenomenological blazar sequence holds in historical sample, but does not exist in quasi-simultaneous sample, and intrinsic correlation between $L_{\rm rad}$ and $谓$ becomes positive in Doppler factor corrected sample. We also analyze if the blazar sequence still exists in subclasses of blazars, i.e., flat-spectrum radio quasars and BL Lacertae objects, with different values of $Y$. To interpret these correlations, we apply a simple scaling model, in which physical parameters of the dissipation region are connected to the location of the dissipation region. We find that the model generated results are highly sensitive to the chosen ranges and distributions of physical parameters. Therefore, we suggest that even though the simple scaling model can reproduce the blazar sequence under specific conditions that have been fine-tuned, such results may not have universal applicability. Further consideration of a more realistic emission model is expected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.09924v1-abstract-full').style.display = 'none'; document.getElementById('2402.09924v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in MNRAS (14 pages, 6 figures, 3 tables)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.02589">arXiv:2401.02589</a> <span> [<a href="https://arxiv.org/pdf/2401.02589">pdf</a>, <a href="https://arxiv.org/format/2401.02589">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="Artificial Intelligence">cs.AI</span> </div> </div> <p class="title is-5 mathjax"> Identification of 4FGL uncertain sources at Higher Resolutions with Inverse Discrete Wavelet Transform </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+H">Haitao Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Luo%2C+Z">Zhijian Luo</a>, <a href="/search/astro-ph?searchtype=author&query=Zeng%2C+X">Xiangtao Zeng</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</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="2401.02589v1-abstract-short" style="display: inline;"> In the forthcoming era of big astronomical data, it is a burden to find out target sources from ground-based and space-based telescopes. Although Machine Learning (ML) methods have been extensively utilized to address this issue, the incorporation of in-depth data analysis can significantly enhance the efficiency of identifying target sources when dealing with massive volumes of astronomical data.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02589v1-abstract-full').style.display = 'inline'; document.getElementById('2401.02589v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.02589v1-abstract-full" style="display: none;"> In the forthcoming era of big astronomical data, it is a burden to find out target sources from ground-based and space-based telescopes. Although Machine Learning (ML) methods have been extensively utilized to address this issue, the incorporation of in-depth data analysis can significantly enhance the efficiency of identifying target sources when dealing with massive volumes of astronomical data. In this work, we focused on the task of finding AGN candidates and identifying BL Lac/FSRQ candidates from the 4FGL DR3 uncertain sources. We studied the correlations among the attributes of the 4FGL DR3 catalogue and proposed a novel method, named FDIDWT, to transform the original data. The transformed dataset is characterized as low-dimensional and feature-highlighted, with the estimation of correlation features by Fractal Dimension (FD) theory and the multi-resolution analysis by Inverse Discrete Wavelet Transform (IDWT). Combining the FDIDWT method with an improved lightweight MatchboxConv1D model, we accomplished two missions: (1) to distinguish the Active Galactic Nuclei (AGNs) from others (Non-AGNs) in the 4FGL DR3 uncertain sources with an accuracy of 96.65%, namely, Mission A; (2) to classify blazar candidates of uncertain type (BCUs) into BL Lacertae objects (BL Lacs) or Flat Spectrum Radio Quasars (FSRQs) with an accuracy of 92.03%, namely, Mission B. There are 1354 AGN candidates in Mission A, 482 BL Lacs candidates and 128 FSRQ candidates in Mission B were found. The results show a high consistency of greater than 98% with the results in previous works. In addition, our method has the advantage of finding less variable and relatively faint sources than ordinary methods. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.02589v1-abstract-full').style.display = 'none'; document.getElementById('2401.02589v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.06746">arXiv:2312.06746</a> <span> [<a href="https://arxiv.org/pdf/2312.06746">pdf</a>, <a href="https://arxiv.org/format/2312.06746">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 Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/JHEP06(2024)028">10.1007/JHEP06(2024)028 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraints on photon mass and dark photon from the Jovian magnetic field </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yan%2C+S">Shi Yan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng Li</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.06746v2-abstract-short" style="display: inline;"> The Jovian magnetic field, being the strongest and largest planetary one in the solar system, could offer us new insights into possible microscopic scale new physics, such as a non-zero mass of the Standard Model (SM) photon or a light dark photon kinetically mixing with the SM photon. We employ the immense data set from the latest Juno mission, which provides us unprecedented information about th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.06746v2-abstract-full').style.display = 'inline'; document.getElementById('2312.06746v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.06746v2-abstract-full" style="display: none;"> The Jovian magnetic field, being the strongest and largest planetary one in the solar system, could offer us new insights into possible microscopic scale new physics, such as a non-zero mass of the Standard Model (SM) photon or a light dark photon kinetically mixing with the SM photon. We employ the immense data set from the latest Juno mission, which provides us unprecedented information about the magnetic field of the gas giant, together with a more rigorous statistical approach compared to the literature, to set strong constraints on the dark photon mass and kinetic mixing parameter, as well as the SM photon mass. The constraint on the dark photon parameters is independent of whether dark photon is (part of) dark matter or not, and serves as the most stringent one in a certain regime of the parameter space. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.06746v2-abstract-full').style.display = 'none'; document.getElementById('2312.06746v2-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 July, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 11 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 8 figures; typos corrected, revised resolutions for the various instrument dynamic ranges in Table 2, results unchanged</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of High Energy Physics 2024.6 (2024): 1-24 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.03072">arXiv:2312.03072</a> <span> [<a href="https://arxiv.org/pdf/2312.03072">pdf</a>, <a href="https://arxiv.org/format/2312.03072">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="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Phenomenology of Spillway Preheating: Equation of State and Gravitational Waves </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mansfield%2C+G">Gareth Mansfield</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Lu%2C+Q">Qianshu Lu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.03072v1-abstract-short" style="display: inline;"> In the canonical tachyonic resonance preheating scenario, only an order one fraction of energy density in the inflaton is transferred to radiation, due to backreaction effects. One possible way to improve the energy transfer efficiency is to allow for the perturbative decays of the resonantly produced daughter particles, which serve as the "spillway" to drain the direct decay products from inflato… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03072v1-abstract-full').style.display = 'inline'; document.getElementById('2312.03072v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.03072v1-abstract-full" style="display: none;"> In the canonical tachyonic resonance preheating scenario, only an order one fraction of energy density in the inflaton is transferred to radiation, due to backreaction effects. One possible way to improve the energy transfer efficiency is to allow for the perturbative decays of the resonantly produced daughter particles, which serve as the "spillway" to drain the direct decay products from inflaton and to reduce the backreaction. In this article, we study two observational consequences of spillway preheating. The first is on the inflationary observables: the scalar spectrum tilt $n_s$ and tensor-to-scalar ratio $r$. The spillway scenario modifies the evolution of the equation of state between the end of inflation and the thermal big bang. As a result, it affects the time elapsed from inflation to the Cosmic Microwave Background (CMB), as well as the fits of inflationary models and their corresponding prediction for $n_s$ and $r$. We map out the equation of state by systematically scanning the parameter space of the spillway scenario, and show that the most efficient spillway scenario predicts a bluer spectrum, compared to the tachyonic preheating scenario. Another consequence is the production of high-frequency gravitational waves (GWs). Comparing the simulation results with those of tachyonic preheating, we find that the existence of spillways leads to sharper-peaked GW spectra with a mildly damped amplitude. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.03072v1-abstract-full').style.display = 'none'; document.getElementById('2312.03072v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">28 pages, 13 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.01122">arXiv:2312.01122</a> <span> [<a href="https://arxiv.org/pdf/2312.01122">pdf</a>, <a href="https://arxiv.org/format/2312.01122">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> <p class="title is-5 mathjax"> GeV Variability Properties of TeV Blazars Detected by Fermi-LAT </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wang%2C+G">Gege Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+X">Xin Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2312.01122v1-abstract-short" style="display: inline;"> Variability is a prominent observational feature of blazars. The high-energy radiation mechanism of jets has always been important but still unclear. In this work, we performed a detailed analysis using Fermi-LAT data across 15 years and obtained GeV light curve information for 78 TeV blazars detected by Fermi. We provided annual GeV fluxes and corresponding spectral indices for the 78 TeV blazars… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01122v1-abstract-full').style.display = 'inline'; document.getElementById('2312.01122v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.01122v1-abstract-full" style="display: none;"> Variability is a prominent observational feature of blazars. The high-energy radiation mechanism of jets has always been important but still unclear. In this work, we performed a detailed analysis using Fermi-LAT data across 15 years and obtained GeV light curve information for 78 TeV blazars detected by Fermi. We provided annual GeV fluxes and corresponding spectral indices for the 78 TeV blazars and thorough monthly GeV fluxes for a subsample of 41 bright blazars. Our results suggest a strong correlation between the $纬$-ray photon index and $\log L_{\rm 纬}$ for the flat spectrum radio quasars (FSRQs) and high-energy-peaked BL Lacs (HBLs). 14 sources in our sample show significant GeV outbursts/flares above the relatively stable, low-flux light curve, with 6 of them showing a clear sharp peak profile in their 5-day binned light curves. We quantified the variability utilizing the fractional variability parameter $F_{\mathrm{var}}$, and found that the flux of the FSRQs showed significantly stronger variability than that of the BL Lacs. The 41 bright blazars in this work are best fit by a log-normal flux distribution. We checked the spectral behavior and found 11 out of the 14 sources show a 'bluer-when-brighter (BWB)' trend, suggesting this spectral behavior for these TeV blazars at the GeV band arises from the mechanism that the synchrotron-self Compton (SSC) process dominates the GeV emission. Our research offers a systematic analysis of the GeV variability properties of TeV blazars and serves as a helpful resource for further associated blazar studies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.01122v1-abstract-full').style.display = 'none'; document.getElementById('2312.01122v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages, 9 figures, accepted for publication in ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.17082">arXiv:2310.17082</a> <span> [<a href="https://arxiv.org/pdf/2310.17082">pdf</a>, <a href="https://arxiv.org/ps/2310.17082">ps</a>, <a href="https://arxiv.org/format/2310.17082">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> <p class="title is-5 mathjax"> Does or did the supernova remnant Cassiopeia A operate as a PeVatron? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2310.17082v1-abstract-short" style="display: inline;"> For decades, supernova remnants (SNRs) have been considered the prime sources of Galactic Cosmic rays (CRs). But whether SNRs can accelerate CR protons to PeV energies and thus dominate CR flux up to the knee is currently under intensive theoretical and phenomenological debate. The direct test of the ability of SNRs to operate as CR PeVatrons can be provided by ultrahigh-energy (UHE;… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17082v1-abstract-full').style.display = 'inline'; document.getElementById('2310.17082v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.17082v1-abstract-full" style="display: none;"> For decades, supernova remnants (SNRs) have been considered the prime sources of Galactic Cosmic rays (CRs). But whether SNRs can accelerate CR protons to PeV energies and thus dominate CR flux up to the knee is currently under intensive theoretical and phenomenological debate. The direct test of the ability of SNRs to operate as CR PeVatrons can be provided by ultrahigh-energy (UHE; $E_纬\geq 100$~TeV) $纬$-rays. In this context, the historical SNR Cassiopeia A (Cas A) is considered one of the most promising target for UHE observations. This paper presents the observation of Cas A and its vicinity by the LHAASO KM2A detector. The exceptional sensitivity of LHAASO KM2A in the UHE band, combined with the young age of Cas A, enabled us to derive stringent model-independent limits on the energy budget of UHE protons and nuclei accelerated by Cas A at any epoch after the explosion. The results challenge the prevailing paradigm that Cas A-type SNRs are major suppliers of PeV CRs in the Milky Way. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.17082v1-abstract-full').style.display = 'none'; document.getElementById('2310.17082v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 3 figures, Accepted by the APJL</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.08845">arXiv:2310.08845</a> <span> [<a href="https://arxiv.org/pdf/2310.08845">pdf</a>, <a href="https://arxiv.org/format/2310.08845">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/10.1126/sciadv.adj2778">10.1126/sciadv.adj2778 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Very high energy gamma-ray emission beyond 10 TeV from GRB 221009A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu%2C+A">A. Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2310.08845v2-abstract-short" style="display: inline;"> The highest energy gamma-rays from gamma-ray bursts (GRBs) have important implications for their radiation mechanism. Here we report for the first time the detection of gamma-rays up to 13 TeV from the brightest GRB 221009A by the Large High Altitude Air-shower Observatory (LHAASO). The LHAASO-KM2A detector registered more than 140 gamma-rays with energies above 3 TeV during 230$-$900s after the t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08845v2-abstract-full').style.display = 'inline'; document.getElementById('2310.08845v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.08845v2-abstract-full" style="display: none;"> The highest energy gamma-rays from gamma-ray bursts (GRBs) have important implications for their radiation mechanism. Here we report for the first time the detection of gamma-rays up to 13 TeV from the brightest GRB 221009A by the Large High Altitude Air-shower Observatory (LHAASO). The LHAASO-KM2A detector registered more than 140 gamma-rays with energies above 3 TeV during 230$-$900s after the trigger. The intrinsic energy spectrum of gamma-rays can be described by a power-law after correcting for extragalactic background light (EBL) absorption. Such a hard spectrum challenges the synchrotron self-Compton (SSC) scenario of relativistic electrons for the afterglow emission above several TeV. Observations of gamma-rays up to 13 TeV from a source with a measured redshift of z=0.151 hints more transparency in intergalactic space than previously expected. Alternatively, one may invoke new physics such as Lorentz Invariance Violation (LIV) or an axion origin of very high energy (VHE) signals. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.08845v2-abstract-full').style.display = 'none'; document.getElementById('2310.08845v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">49pages, 11figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science Advances, 9, eadj2778 (2023) 15 November 2023 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.07212">arXiv:2309.07212</a> <span> [<a href="https://arxiv.org/pdf/2309.07212">pdf</a>, <a href="https://arxiv.org/format/2309.07212">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="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Probing New Physics with High-Redshift Quasars: Axions and Non-standard Cosmology </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Sun%2C+C">Chen Sun</a>, <a href="/search/astro-ph?searchtype=author&query=Buen-Abad%2C+M+A">Manuel A. Buen-Abad</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</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="2309.07212v2-abstract-short" style="display: inline;"> The Hubble diagram of quasars, as candidates to ``standardizable" candles, has been used to measure the expansion history of the Universe at late times, up to very high redshifts ($z \sim 7$). It has been shown that this history, as inferred from the quasar dataset, deviates at $\gtrsim 3 蟽$ level from the concordance ($螞$CDM) cosmology model preferred by the cosmic microwave background (CMB) and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07212v2-abstract-full').style.display = 'inline'; document.getElementById('2309.07212v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.07212v2-abstract-full" style="display: none;"> The Hubble diagram of quasars, as candidates to ``standardizable" candles, has been used to measure the expansion history of the Universe at late times, up to very high redshifts ($z \sim 7$). It has been shown that this history, as inferred from the quasar dataset, deviates at $\gtrsim 3 蟽$ level from the concordance ($螞$CDM) cosmology model preferred by the cosmic microwave background (CMB) and other datasets. In this article, we investigate whether new physics beyond $螞$CDM (B$螞$CDM) or beyond the Standard Model (BSM) could make the quasar data consistent with the concordance model. We first show that an effective redshift-dependent relation between the quasar UV and X-ray luminosities, complementing previous phenomenological work in the literature, can potentially remedy the discrepancy. Such a redshift dependence can be realized in a BSM model with axion-photon conversion in the intergalactic medium (IGM), although the preferred parameter space is {in tension with various other astrophysical constraints on axions, at a level} depending on the specific assumptions made regarding the IGM magnetic field. We briefly discuss a variation of the axion model that could evade these astrophysical constraints. On the other hand, we show that models beyond $螞$CDM such as one with a varying dark energy equation of state ($w$CDM) or the phenomenological cosmographic model with a polynomial expansion of the luminosity distance, cannot alleviate the tension. The code for our analysis, based on \texttt{emcee}~\cite{Foreman_Mackey_2013} and \texttt{corner.py}~\cite{corner}, is publicly available at \href{https://github.com/ChenSun-Phys/high\_z\_candles.git}{\tt github.com/ChenSun-Phys/high\_z\_candles}. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.07212v2-abstract-full').style.display = 'none'; document.getElementById('2309.07212v2-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10+3 pages, 4 figures, 4 tables, 3 appendices; reference updated; matched to the published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> LA-UR-23-29579 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2307.07163">arXiv:2307.07163</a> <span> [<a href="https://arxiv.org/pdf/2307.07163">pdf</a>, <a href="https://arxiv.org/format/2307.07163">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> <p class="title is-5 mathjax"> Characterizing the emission region property of blazars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+W">Wenxin Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+L">Lixia Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Strigachev%2C+A+A">Anton A. Strigachev</a>, <a href="/search/astro-ph?searchtype=author&query=Bachev%2C+R+S">Rumen S. Bachev</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+J">Jianghe Yang</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="2307.07163v1-abstract-short" style="display: inline;"> The studies and constraints on the emission region are crucial to the blazar radiation mechanism. Yet the previous works mainly focus on individual sources. In this work, we make use of the largest and the latest spectral energy distribution (SED) fitting results in the literature to statistically study the blazar emission region property in the framework of leptonic one-zone. Our results reveal (… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.07163v1-abstract-full').style.display = 'inline'; document.getElementById('2307.07163v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2307.07163v1-abstract-full" style="display: none;"> The studies and constraints on the emission region are crucial to the blazar radiation mechanism. Yet the previous works mainly focus on individual sources. In this work, we make use of the largest and the latest spectral energy distribution (SED) fitting results in the literature to statistically study the blazar emission region property in the framework of leptonic one-zone. Our results reveal (1) FSRQs show lower electron energy ($纬_{\rm p} \lesssim 1.6 \times 10^{3}$) than BL Lacs and tend to have a stronger magnetic field ($B$) and smaller electron-to-magnetic energy ratio ($U_{\rm e}/U_{\rm B}$) than BL Lacs; (2) we find the electro-magnetic equipartition would rather happen in the jets of BL Lacs than happen in the jets of FSRQs; (3) there are 682 blazars with a magnetic field weaker critical value of generating the Kelvin-Helmholtz instability, thus one-third of the blazars in our sample are able to produce this instability; (4) the distance ($d_{\rm em}$) between the emission region and the central black hole (BH) is in the scale of $\sim$0.1 pc, the location of the emission region may be evenly distributed inside and outside the broad line region (BLR). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2307.07163v1-abstract-full').style.display = 'none'; document.getElementById('2307.07163v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 5 figures, 2 tables. Accepted to ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.17405">arXiv:2306.17405</a> <span> [<a href="https://arxiv.org/pdf/2306.17405">pdf</a>, <a href="https://arxiv.org/format/2306.17405">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> <p class="title is-5 mathjax"> General Physical Properties of Fermi blazars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Y">Yongyun Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Gu%2C+Q">Qiusheng Gu</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Yu%2C+X">Xiaoling Yu</a>, <a href="/search/astro-ph?searchtype=author&query=Zhong%2C+X">Xiaogu Zhong</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+H">Hongyu Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+N">Nan Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Xiong%2C+D">Dingrong Xiong</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+X">Xiaotong Guo</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="2306.17405v1-abstract-short" style="display: inline;"> We study the general physical properties of Fermi blazars using the Fermi fourth source catalog data (4FGL-DR2). The quasi-simultaneous multiwavelength data of Fermi blazar are fitted by using the one-zone leptonic model to obtain some physical parameters, such as jet power, magnetic field and Doppler factor. We study the distributions of the derived physical parameter as a function of black hole… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.17405v1-abstract-full').style.display = 'inline'; document.getElementById('2306.17405v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.17405v1-abstract-full" style="display: none;"> We study the general physical properties of Fermi blazars using the Fermi fourth source catalog data (4FGL-DR2). The quasi-simultaneous multiwavelength data of Fermi blazar are fitted by using the one-zone leptonic model to obtain some physical parameters, such as jet power, magnetic field and Doppler factor. We study the distributions of the derived physical parameter as a function of black hole mass and accretion disk luminosity. The main results are as follows. (1) For a standard thin accretion disk, the jet kinetic power of most FSRQs can be explained by the BP mechanism. However, the jet kinetic power of most BL Lacs can not be explained by both the BZ mechanism or the BP mechanism. The BL Lacs may have ADAFs surrounding their massive black holes. (2) After excluding the redshift, there is a moderately strong correlation between the jet kinetic power and jet radiation power and the accretion disk luminosity for Fermi blazars. These results confirm a close connection between jet and accretion. The jet kinetic power is slightly larger than the accretion disk luminosity for Fermi blazars. (3) There is a significant correlation between jet kinetic power and gamma-ray luminosity and radio luminosity for Fermi blazars, which suggests that gamma-ray luminosity and radio luminosity can be used to indicate the jet kinetic power. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.17405v1-abstract-full').style.display = 'none'; document.getElementById('2306.17405v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13pages,8 figures, accept for publication in ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.17030">arXiv:2305.17030</a> <span> [<a href="https://arxiv.org/pdf/2305.17030">pdf</a>, <a href="https://arxiv.org/format/2305.17030">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="High Energy Physics - Phenomenology">hep-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/10.3847/1538-4365/acfd29">10.3847/1538-4365/acfd29 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The First LHAASO Catalog of Gamma-Ray Sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2305.17030v2-abstract-short" style="display: inline;"> We present the first catalog of very-high energy and ultra-high energy gamma-ray sources detected by the Large High Altitude Air Shower Observatory (LHAASO). The catalog was compiled using 508 days of data collected by the Water Cherenkov Detector Array (WCDA) from March 2021 to September 2022 and 933 days of data recorded by the Kilometer Squared Array (KM2A) from January 2020 to September 2022.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17030v2-abstract-full').style.display = 'inline'; document.getElementById('2305.17030v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.17030v2-abstract-full" style="display: none;"> We present the first catalog of very-high energy and ultra-high energy gamma-ray sources detected by the Large High Altitude Air Shower Observatory (LHAASO). The catalog was compiled using 508 days of data collected by the Water Cherenkov Detector Array (WCDA) from March 2021 to September 2022 and 933 days of data recorded by the Kilometer Squared Array (KM2A) from January 2020 to September 2022. This catalog represents the main result from the most sensitive large coverage gamma-ray survey of the sky above 1 TeV, covering declination from $-$20$^{\circ}$ to 80$^{\circ}$. In total, the catalog contains 90 sources with an extended size smaller than $2^\circ$ and a significance of detection at $> 5蟽$. Based on our source association criteria, 32 new TeV sources are proposed in this study. Among the 90 sources, 43 sources are detected with ultra-high energy ($E > 100$ TeV) emission at $> 4蟽$ significance level. We provide the position, extension, and spectral characteristics of all the sources in this catalog. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17030v2-abstract-full').style.display = 'none'; document.getElementById('2305.17030v2-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> 27 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, 13 figures, 4 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Supplement Series, 271 (2024) 25 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.10102">arXiv:2305.10102</a> <span> [<a href="https://arxiv.org/pdf/2305.10102">pdf</a>, <a href="https://arxiv.org/format/2305.10102">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1538-3873/acb291">10.1088/1538-3873/acb291 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The beaming effect for Fermi-LAT-detected FR-I radio galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ye%2C+X">Xu-Hong Ye</a>, <a href="/search/astro-ph?searchtype=author&query=Zeng%2C+X">Xiang-Tao Zeng</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+D">Dan-Yi Huang</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+Z">Zhuang Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Pei%2C+Z">Zhi-Yuan Pei</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jun-Hui Fan</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="2305.10102v1-abstract-short" style="display: inline;"> Our knowledge of Giga-electron volt (GeV) radio galaxies has been revolutionized by the Fermi-LAT Telescope, which provides an excellent opportunity to study the physical properties of GeV radio galaxies. According to the radio power and morphology, radio galaxies can be separated into Fanaroff-Riley Type I radio galaxies (FR-Is) and Type II radio galaxies (FR-IIs). In this paper, we consider the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.10102v1-abstract-full').style.display = 'inline'; document.getElementById('2305.10102v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.10102v1-abstract-full" style="display: none;"> Our knowledge of Giga-electron volt (GeV) radio galaxies has been revolutionized by the Fermi-LAT Telescope, which provides an excellent opportunity to study the physical properties of GeV radio galaxies. According to the radio power and morphology, radio galaxies can be separated into Fanaroff-Riley Type I radio galaxies (FR-Is) and Type II radio galaxies (FR-IIs). In this paper, we consider the unification of FR-Is and BL Lacertae objects (BL Lacs), and assume FR-Is to be a standard candle to discuss the beaming effect for Fermi-LAT-detected FR-Is. Our main conclusions are as follows: (1) The estimated Doppler factors for 30 Fermi-LAT-detected FR-Is are in a range of $未_{\rm{I}}=0.88-7.49$. The average Doppler factor ($<未_{\rm{I}}>=2.56\pm0.30$) of the 30 FR-Is is smaller than that ($<未_{\rm{BL}}>=10.28\pm2.03$) of the 126 Fermi-LAT-detected BL Lacs, supporting the unification model that FR-Is are regarded as the misaligned BL Lacs with smaller Doppler factors; (2) We propose that different regions of FR-Is in the plot of the $纬$-ray luminosity against the photon spectral index $(\log L_纬-伪_{\rm{ph}})$ may indicate the different beaming effects; (3) The average Doppler factor of the 6 TeV FR-Is is similar to that of the 24 non-TeV FR-Is, which implies that the difference between the TeV and GeV emissions is not driven by the beaming effect in the Fermi-LAT-detected FR-I samples. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.10102v1-abstract-full').style.display = 'none'; document.getElementById('2305.10102v1-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 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 6 figures, 2 tables. publication in PASP</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2023PASP..135a4101Y </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.05372">arXiv:2305.05372</a> <span> [<a href="https://arxiv.org/pdf/2305.05372">pdf</a>, <a href="https://arxiv.org/format/2305.05372">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/10.1103/PhysRevLett.131.151001">10.1103/PhysRevLett.131.151001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Measurement of ultra-high-energy diffuse gamma-ray emission of the Galactic plane from 10 TeV to 1 PeV with LHAASO-KM2A </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Q">Q. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W+Y">W. Y. Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+A+M">A. M. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Lin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Q+H">Q. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a> , et al. (255 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="2305.05372v2-abstract-short" style="display: inline;"> The diffuse Galactic $纬$-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this work we report the measurements of diffuse $纬$-rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer ar… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.05372v2-abstract-full').style.display = 'inline'; document.getElementById('2305.05372v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.05372v2-abstract-full" style="display: none;"> The diffuse Galactic $纬$-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this work we report the measurements of diffuse $纬$-rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner ($15^{\circ}<l<125^{\circ}$, $|b|<5^{\circ}$) and outer ($125^{\circ}<l<235^{\circ}$, $|b|<5^{\circ}$) Galactic plane are detected with $29.1蟽$ and $12.7蟽$ significance, respectively. The outer Galactic plane diffuse emission is detected for the first time in the very- to ultra-high-energy domain ($E>10$~TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of $-2.99\pm0.04$, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of $\sim3$ than the prediction. A similar spectrum with an index of $-2.99\pm0.07$ is found in the outer Galaxy region, and the absolute flux for $10\lesssim E\lesssim60$ TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.05372v2-abstract-full').style.display = 'none'; document.getElementById('2305.05372v2-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 9 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 8 figures, 5 tables; accepted for publication in Physical Review Letters; source mask file provided as ancillary file</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 131, 151001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.05551">arXiv:2304.05551</a> <span> [<a href="https://arxiv.org/pdf/2304.05551">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <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/10.3847/1538-4365/acc57f">10.3847/1538-4365/acc57f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> General Physical Properties of Gamma-Ray-emitting Radio Galaxies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+Y">Yongyun Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Gu%2C+Q">Qiusheng Gu</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Yu%2C+X">Xiaoling Yu</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+N">Nan Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Xiong%2C+D">Dingrong Xiong</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+X">Xiaotong Guo</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="2304.05551v1-abstract-short" style="display: inline;"> We study the radio galaxies with known redshift detected by the Fermi satellite after 10 years of data (4FGL-DR2). We use a one-zone leptonic model to fit the quasi-simultaneous multiwavelength data of these radio galaxies and study the distributions of the derived physical parameter as a function of black hole mass and accretion disk luminosity. The main results are as follows. (1) We find that t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.05551v1-abstract-full').style.display = 'inline'; document.getElementById('2304.05551v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.05551v1-abstract-full" style="display: none;"> We study the radio galaxies with known redshift detected by the Fermi satellite after 10 years of data (4FGL-DR2). We use a one-zone leptonic model to fit the quasi-simultaneous multiwavelength data of these radio galaxies and study the distributions of the derived physical parameter as a function of black hole mass and accretion disk luminosity. The main results are as follows. (1) We find that the jet kinetic power of most radio galaxies can be explained by the hybrid jet model based on ADAFs surrounding Kerr black holes. (2) After excluding the redshift, there is a significant correlation between the radiation jet power and the accretion disk luminosity, while the jet kinetic power is weakly correlated with the accretion disk luminosity. (3) We also find a significant correlation between inverse Compton luminosity and synchrotron luminosity. The slope of the correlation for radio galaxies is consistent with the synchrotron self-Compton (SSC) process. The result may suggest that the high-energy component of radio galaxies is dominated by the SSC process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.05551v1-abstract-full').style.display = 'none'; document.getElementById('2304.05551v1-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 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages,7 figures, accept for publication in ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.03975">arXiv:2304.03975</a> <span> [<a href="https://arxiv.org/pdf/2304.03975">pdf</a>, <a href="https://arxiv.org/ps/2304.03975">ps</a>, <a href="https://arxiv.org/format/2304.03975">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/stad1063">10.1093/mnras/stad1063 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Intra-night optical flux and polarization variability of BL~Lacertae during its 2020 $-$ 2021 high state </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bachev%2C+R">Rumen Bachev</a>, <a href="/search/astro-ph?searchtype=author&query=Tripathi%2C+T">Tushar Tripathi</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+A+C">Alok C. Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Kushwaha%2C+P">Pankaj Kushwaha</a>, <a href="/search/astro-ph?searchtype=author&query=Strigachev%2C+A">Anton Strigachev</a>, <a href="/search/astro-ph?searchtype=author&query=Kurtenkov%2C+A">Alexander Kurtenkov</a>, <a href="/search/astro-ph?searchtype=author&query=Nikolov%2C+Y">Yanko Nikolov</a>, <a href="/search/astro-ph?searchtype=author&query=Boeva%2C+S">Svetlana Boeva</a>, <a href="/search/astro-ph?searchtype=author&query=Damljanovic%2C+G">Goran Damljanovic</a>, <a href="/search/astro-ph?searchtype=author&query=Vince%2C+O">Oliver Vince</a>, <a href="/search/astro-ph?searchtype=author&query=Stojanovic%2C+M">Milan Stojanovic</a>, <a href="/search/astro-ph?searchtype=author&query=Kishore%2C+S">Shubham Kishore</a>, <a href="/search/astro-ph?searchtype=author&query=Gaur%2C+H">Haritma Gaur</a>, <a href="/search/astro-ph?searchtype=author&query=Dhiman%2C+V">Vinit Dhiman</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Kalita%2C+N">Nibedita Kalita</a>, <a href="/search/astro-ph?searchtype=author&query=Spassov%2C+B">Borislav Spassov</a>, <a href="/search/astro-ph?searchtype=author&query=Semkov%2C+E">Evgeni Semkov</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="2304.03975v1-abstract-short" style="display: inline;"> In this work, we report the presence of rapid intra-night optical variations in both -- flux and polarization of the blazar BL Lacertae during its unprecedented 2020--2021 high state of brightness. The object showed significant flux variability and some color changes, but no firmly detectable time delays between the optical bands. The linear polarization was also highly variable in both -- polariz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.03975v1-abstract-full').style.display = 'inline'; document.getElementById('2304.03975v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.03975v1-abstract-full" style="display: none;"> In this work, we report the presence of rapid intra-night optical variations in both -- flux and polarization of the blazar BL Lacertae during its unprecedented 2020--2021 high state of brightness. The object showed significant flux variability and some color changes, but no firmly detectable time delays between the optical bands. The linear polarization was also highly variable in both -- polarization degree and angle (EVPA). The object was observed from several observatories throughout the world, covering in a total of almost 300 hours during 66 nights. Based on our results, we suggest, that the changing Doppler factor of an ensemble of independent emitting regions, travelling along a curved jet that at some point happens to be closely aligned with the line of sight can successfully reproduce our observations during this outburst. This is one of the most extensive variability studies of the optical polarization of a blazar on intra-night timescales. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.03975v1-abstract-full').style.display = 'none'; document.getElementById('2304.03975v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">23 pages,7 figures, 5 Tables (2 as appendix). 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/2303.16849">arXiv:2303.16849</a> <span> [<a href="https://arxiv.org/pdf/2303.16849">pdf</a>, <a href="https://arxiv.org/format/2303.16849">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> <p class="title is-5 mathjax"> Dwarf Galaxy Discoveries from the KMTNet Supernova Program III. the Milky-Way Analog NGC~2997 Group </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+T+J">Tony Junjing Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Moon%2C+D">Dae-Sik Moon</a>, <a href="/search/astro-ph?searchtype=author&query=Park%2C+H+S">Hong Soo Park</a>, <a href="/search/astro-ph?searchtype=author&query=Zaritsky%2C+D">Dennis Zaritsky</a>, <a href="/search/astro-ph?searchtype=author&query=Kim%2C+S+C">Sang Chul Kim</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+Y">Youngdae Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+T+S">Ting S. Li</a>, <a href="/search/astro-ph?searchtype=author&query=Ni%2C+Y+Q">Yuan Qi Ni</a>, <a href="/search/astro-ph?searchtype=author&query=Shin%2C+J">Jeehye Shin</a>, <a href="/search/astro-ph?searchtype=author&query=Cha%2C+S">Sang-Mok Cha</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+Y">Yongseok Lee</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="2303.16849v2-abstract-short" style="display: inline;"> We present the discovery of 48 new and the analysis of 55, including 7 previously discovered, dwarf galaxy candidates around the giant spiral galaxy NGC~2997 using deep $BVI$ images from the KMTNet Supernova Program. Their $V$-band central surface brightness and total absolute magnitudes are in the range of 20.3--26.7 mag arcsec$^{-2}$ and --(8.02--17.69) mag, respectively, while the $I$-band effe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16849v2-abstract-full').style.display = 'inline'; document.getElementById('2303.16849v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.16849v2-abstract-full" style="display: none;"> We present the discovery of 48 new and the analysis of 55, including 7 previously discovered, dwarf galaxy candidates around the giant spiral galaxy NGC~2997 using deep $BVI$ images from the KMTNet Supernova Program. Their $V$-band central surface brightness and total absolute magnitudes are in the range of 20.3--26.7 mag arcsec$^{-2}$ and --(8.02--17.69) mag, respectively, while the $I$-band effective radii are 0.14--2.97 kpc. We obtain $伪$ $\simeq$ --1.43 $\pm$ 0.02 for the faint-end slope of their luminosity function, comparable to previously measured values but shallower than theoretical predictions based on $螞$CDM models. The distance-independent distributions of their mass and color suggest that the group could have recently accreted new massive members from the surrounding fields. The systematically bluer colors of the brighter members indicate younger stellar population and higher star formation activities in them, which appears to be consistent with similar findings from the SAGA or ELVES survey. We suggest that the massive and bluer dwarf galaxies in the group have experienced less environmental quenching due to their recent accretion, while environmental quenching is more effective for the low-mass members. The interpretation of NGC~2997 being populationally young with recent accretion of massive members is also consistent with the overall morphological distribution of the dwarf galaxies showing a lack of morphologically evolved candidates but a plethora of irregularly shaped ones. Our detection rate of dwarf galaxy candidates in the NGC~2997 group and their inferred star formation activities are comparable to those found in Milky Way analog systems from recent surveys within the magnitude limit M$_{V}$ $\lesssim$ --13 mag. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16849v2-abstract-full').style.display = 'none'; document.getElementById('2303.16849v2-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 July, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 14 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.16383">arXiv:2303.16383</a> <span> [<a href="https://arxiv.org/pdf/2303.16383">pdf</a>, <a href="https://arxiv.org/ps/2303.16383">ps</a>, <a href="https://arxiv.org/format/2303.16383">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> <p class="title is-5 mathjax"> The jet apparent motion and central engine study of Fermi blazars </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H+B">H. B. Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+J+T">J. T. Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J+H">J. H. Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Pei%2C+Z+Y">Z. Y. Pei</a>, <a href="/search/astro-ph?searchtype=author&query=Luo%2C+Z+J">Z. J. Luo</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+S+H">S. H. Zhang</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="2303.16383v1-abstract-short" style="display: inline;"> The study of blazar jet has been performed for several decades via the VLBI technique, while its generation and propagation stay unclear. In the present work, we compiled a sample of 407 VLBI detected \textit{Fermi} blazars (VFBs) and studied the correlations between apparent velocity (${\rm log}\,尾_{\rm app}$) and jet/accretion disk properties. We found a positive correlation between $纬$-ray lumi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16383v1-abstract-full').style.display = 'inline'; document.getElementById('2303.16383v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.16383v1-abstract-full" style="display: none;"> The study of blazar jet has been performed for several decades via the VLBI technique, while its generation and propagation stay unclear. In the present work, we compiled a sample of 407 VLBI detected \textit{Fermi} blazars (VFBs) and studied the correlations between apparent velocity (${\rm log}\,尾_{\rm app}$) and jet/accretion disk properties. We found a positive correlation between $纬$-ray luminosity (${\rm log}\,L_{\rm 纬}$) and ${\rm log}\,尾_{\rm app}$, the correlation suggests that the apparent motion of jet knot is related to the jet power. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16383v1-abstract-full').style.display = 'none'; document.getElementById('2303.16383v1-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">11 pages, 7 figures, 3 tables</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Published on MNRAS in 2022 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.10557">arXiv:2303.10557</a> <span> [<a href="https://arxiv.org/pdf/2303.10557">pdf</a>, <a href="https://arxiv.org/format/2303.10557">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="High Energy Physics - Phenomenology">hep-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/10.3847/1538-4357/acca85">10.3847/1538-4357/acca85 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exploring TeV candidates of Fermi blazars through machine learning </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+J+T">J. T. Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Lin%2C+C">C. Lin</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H+B">H. B. Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J+H">J. H. Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+G+G">G. G. Wang</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="2303.10557v1-abstract-short" style="display: inline;"> In this work, we make use of a supervised machine learning algorithm based on Logistic Regression (LR) to select TeV blazar candidates from the 4FGL-DR2 / 4LAC-DR2, 3FHL, 3HSP, and 2BIGB catalogs. LR constructs a hyperplane based on a selection of optimal parameters, named features, and hyper-parameters whose values control the learning process and determine the values of features that a learning… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.10557v1-abstract-full').style.display = 'inline'; document.getElementById('2303.10557v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.10557v1-abstract-full" style="display: none;"> In this work, we make use of a supervised machine learning algorithm based on Logistic Regression (LR) to select TeV blazar candidates from the 4FGL-DR2 / 4LAC-DR2, 3FHL, 3HSP, and 2BIGB catalogs. LR constructs a hyperplane based on a selection of optimal parameters, named features, and hyper-parameters whose values control the learning process and determine the values of features that a learning algorithm ends up learning, to discriminate TeV blazars from non-TeV blazars. In addition, it gives the probability (or logistic) that a source may be considered as a TeV blazar candidate. Non-TeV blazars with logistics greater than 80% are considered high-confidence TeV candidates. Using this technique, we identify 40 high-confidence TeV candidates from the 4FGL-DR2 / 4LAC-DR2 blazars and we build the feature hyper-plane to distinguish TeV and non-TeV blazars. We also calculate the hyper-planes for the 3FHL, 3HSP, and 2BIGB. Finally, we construct the broadband spectral energy distributions (SED) for the 40 candidates, testing for their detectability with various instruments. We find that 7 of them are likely to be detected by existing or upcoming IACT observatories, while 1 could be observed with EAS particle detector arrays. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.10557v1-abstract-full').style.display = 'none'; document.getElementById('2303.10557v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.09845">arXiv:2303.09845</a> <span> [<a href="https://arxiv.org/pdf/2303.09845">pdf</a>, <a href="https://arxiv.org/ps/2303.09845">ps</a>, <a href="https://arxiv.org/format/2303.09845">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/10.3847/1538-4357/acc329">10.3847/1538-4357/acc329 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The `blazar sequence' in TeV band </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ouyang%2C+Z">Zhihao Ouyang</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+J">Jianzhen Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Strigachev%2C+A+A">Anton A. Strigachev</a>, <a href="/search/astro-ph?searchtype=author&query=Bachev%2C+R+S">Rumen S. Bachev</a>, <a href="/search/astro-ph?searchtype=author&query=Zeng%2C+X">Xiangtao Zeng</a>, <a href="/search/astro-ph?searchtype=author&query=Manganaro%2C+M">Marina Manganaro</a>, <a href="/search/astro-ph?searchtype=author&query=Xue%2C+R">Rui Xue</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+Z">Zelin Li</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</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="2303.09845v1-abstract-short" style="display: inline;"> The `blazar sequence' has been proposed for more than 20 years, yet its nature is still unclear. In this work, for the first time, we expand this topic to the TeV band by using a sample of 58 TeV blazars including 48 blazars in the quiescent state and 21 blazars in the flaring state. We investigate the correlation between the TeV luminosity, which has been compensated for attenuation from extragal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.09845v1-abstract-full').style.display = 'inline'; document.getElementById('2303.09845v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.09845v1-abstract-full" style="display: none;"> The `blazar sequence' has been proposed for more than 20 years, yet its nature is still unclear. In this work, for the first time, we expand this topic to the TeV band by using a sample of 58 TeV blazars including 48 blazars in the quiescent state and 21 blazars in the flaring state. We investigate the correlation between the TeV luminosity, which has been compensated for attenuation from extragalactic background light, and the synchrotron peak frequency. We note that there is no correlation between TeV luminosity and peak frequency in the quiescent state and a strong anti-correlation in the flaring state for the observed value. However, there is a strong positive correlation in both the quiescent state and the flaring state for the intrinsic value. This indicates that the blazar sequence is shown in the flaring state rather than in the quiescent state for the observed value and the blazar sequence is not present in both two states after removing the beaming effect. In addition, to confirm whether the beaming effect results in the blazar sequence, we compare the \textit{Fermi} $纬$-ray luminosity between the quiescent state and the flaring state. We find the \textit{Fermi} $纬$-ray luminosity in the flaring state is greater than that in the quiescent state and the Doppler factor in the flaring state is greater. We suggest the blazar sequence in the flaring state may be due to the stronger beaming effect. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.09845v1-abstract-full').style.display = 'none'; document.getElementById('2303.09845v1-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 4 figures and 4 tables. Accepted to APJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.03406">arXiv:2303.03406</a> <span> [<a href="https://arxiv.org/pdf/2303.03406">pdf</a>, <a href="https://arxiv.org/format/2303.03406">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 Physics - Phenomenology">hep-ph</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="High Energy Physics - Theory">hep-th</span> </div> </div> <p class="title is-5 mathjax"> New inflationary probes of axion dark matter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">Xingang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng 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="2303.03406v2-abstract-short" style="display: inline;"> If a light axion is present during inflation and becomes part of dark matter afterwards, its quantum fluctuations contribute to dark matter isocurvature. In this article, we introduce a whole new suite of cosmological observables for axion isocurvature, which could help test the presence of axions, as well as its coupling to the inflaton and other heavy spectator fields during inflation such as th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.03406v2-abstract-full').style.display = 'inline'; document.getElementById('2303.03406v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.03406v2-abstract-full" style="display: none;"> If a light axion is present during inflation and becomes part of dark matter afterwards, its quantum fluctuations contribute to dark matter isocurvature. In this article, we introduce a whole new suite of cosmological observables for axion isocurvature, which could help test the presence of axions, as well as its coupling to the inflaton and other heavy spectator fields during inflation such as the radial mode of the Peccei-Quinn field. They include correlated clock signals in the curvature and isocurvature spectra, and mixed cosmological-collider non-Gaussianities involving both curvature and isocurvature fluctuations with shapes and running unconstrained by the current data analyses. Taking into account of the existing strong constraints on axion isocurvature fluctuations from the CMB, these novel signals could still be sizable and potentially observable. In some models, the signals, if observed, could even help us significantly narrow down the range of the inflationary Hubble scale, a crucial parameter difficult to be determined in general, independent of the tensor mode. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.03406v2-abstract-full').style.display = 'none'; document.getElementById('2303.03406v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">45 pages, 15 figures, updated according to the version published in JHEP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.13395">arXiv:2212.13395</a> <span> [<a href="https://arxiv.org/pdf/2212.13395">pdf</a>, <a href="https://arxiv.org/format/2212.13395">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1538-3873/ac98e0">10.1088/1538-3873/ac98e0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variability and Spectral Behavior of Gamma-ray Flares of 3C 279 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Wang%2C+G">Gege Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J">Jinting Cai</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="2212.13395v1-abstract-short" style="display: inline;"> 3C 279 showed enhanced flux variations in Fermi-LAT 纬-ray observations from January to June 2018. We present a detailed Fermi-LAT analysis to investigate the variability and spectral behaviors of 3C 279 during the 纬-ray flares in 2018. In this work, we analyzed the 纬-ray spectra and found that the spectra in either the flaring or quiescent states do not show any clear breaks (or cutoffs). This ind… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.13395v1-abstract-full').style.display = 'inline'; document.getElementById('2212.13395v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.13395v1-abstract-full" style="display: none;"> 3C 279 showed enhanced flux variations in Fermi-LAT 纬-ray observations from January to June 2018. We present a detailed Fermi-LAT analysis to investigate the variability and spectral behaviors of 3C 279 during the 纬-ray flares in 2018. In this work, we analyzed the 纬-ray spectra and found that the spectra in either the flaring or quiescent states do not show any clear breaks (or cutoffs). This indicates that the dissipation region is outside the broad-line region, and the energy dissipation may be due to the inverse Compton process of scattering the dust torus infrared photons, this result is also consistent with that in Tolamatti et al. An external inverse Compton scattering of dusty torus (DT) photons is employed to calculate the broadband spectral energy distribution (SED). This model was further supported by the fact that we found flare decay timescale was consistent with the cooling time of relativistic electrons through DT photons. During the SED modeling, a relatively harder spectrum for the electron energy distribution (EED) is found and suggests these electrons may not be accelerated by the shock that happened in the dissipation region. Besides, the magnetic reconnection is also ruled out due to a low magnetization ratio. Thus, we suggest an injection of higher-energy electrons from outside the blob and raising the flare. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.13395v1-abstract-full').style.display = 'none'; document.getElementById('2212.13395v1-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> 27 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 6 figures, published in the Publications of the Astronomical Society of the Pacific</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.07033">arXiv:2212.07033</a> <span> [<a href="https://arxiv.org/pdf/2212.07033">pdf</a>, <a href="https://arxiv.org/format/2212.07033">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> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad2269">10.3847/1538-4357/ad2269 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Cosmic Reionization On Computers: Statistics, Physical Properties and Environment of Lyman Limit Systems at $z\sim6$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jiawen Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+H">Hanjue Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Avestruz%2C+C">Camille Avestruz</a>, <a href="/search/astro-ph?searchtype=author&query=Gnedin%2C+N+Y">Nickolay Y. Gnedin</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="2212.07033v2-abstract-short" style="display: inline;"> Lyman limit systems (LLSs) are dense hydrogen clouds with high enough HI column densities to absorb Lyman continuum photons emitted from distant quasars. Their high column densities imply an origin in dense environments; however, the statistics and distribution of LLSs at high redshifts still remain uncertain. In this paper, we use self-consistent radiative transfer cosmological simulations from t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.07033v2-abstract-full').style.display = 'inline'; document.getElementById('2212.07033v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.07033v2-abstract-full" style="display: none;"> Lyman limit systems (LLSs) are dense hydrogen clouds with high enough HI column densities to absorb Lyman continuum photons emitted from distant quasars. Their high column densities imply an origin in dense environments; however, the statistics and distribution of LLSs at high redshifts still remain uncertain. In this paper, we use self-consistent radiative transfer cosmological simulations from the "Cosmic Reionization On Computers" (CROC) project to study the physical properties of LLSs at the tail end of cosmic reionization at $z\sim6$. We generate 3000 synthetic quasar sightlines to obtain a large number of LLS samples in the simulations. In addition, with the high physical fidelity and resolution of CROC, we are able to quantify the association between these LLS samples and nearby galaxies. Our results show that the fraction LLSs spatially associated with nearby galaxies is increasing with the HI column density. Moreover, we find that LLSs that are not near any galaxy typically reside in filamentary structures connecting neighboring galaxies in the intergalactic medium (IGM). This quantification of the distribution and associations of LLSs to large scale structures informs our understanding of the IGM-galaxy connection during the Epoch of Reionization, and provides a theoretical basis for interpreting future observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.07033v2-abstract-full').style.display = 'none'; document.getElementById('2212.07033v2-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, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">11 pages, 10 figures, submitted to ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2024 ApJ 963 45 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.04181">arXiv:2212.04181</a> <span> [<a href="https://arxiv.org/pdf/2212.04181">pdf</a>, <a href="https://arxiv.org/ps/2212.04181">ps</a>, <a href="https://arxiv.org/format/2212.04181">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/aca801">10.3847/1538-4357/aca801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optical flux and spectral variability of BL Lacertae during its historical high outburst in 2020 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Kalita%2C+N">Nibedita Kalita</a>, <a href="/search/astro-ph?searchtype=author&query=Yuan%2C+Y">Yuhai Yuan</a>, <a href="/search/astro-ph?searchtype=author&query=Gu%2C+M">Minfeng Gu</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Mizuno%2C+Y">Yosuke Mizuno</a>, <a href="/search/astro-ph?searchtype=author&query=Jiang%2C+P">Peng Jiang</a>, <a href="/search/astro-ph?searchtype=author&query=Gupta%2C+A+C">Alok C. Gupta</a>, <a href="/search/astro-ph?searchtype=author&query=Zhou%2C+H">Hongyan Zhou</a>, <a href="/search/astro-ph?searchtype=author&query=Pan%2C+X">Xiang Pan</a>, <a href="/search/astro-ph?searchtype=author&query=Strigachev%2C+A+A">Anton A. Strigachev</a>, <a href="/search/astro-ph?searchtype=author&query=Bachev%2C+R+S">Rumen S. Bachev</a>, <a href="/search/astro-ph?searchtype=author&query=Cui%2C+L">Lang Cui</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="2212.04181v1-abstract-short" style="display: inline;"> BL Lacertae had undergone a series of historical high flux activity over a year, from August 2020 in the optical to VHE $纬$-rays. In this paper, we report on optical flux and spectral variability of the first historical maxima outburst event during October-November in g, r and i bands with the 1.26m telescope at Xinglong observatory, China. We detected significant intranight variations with amplit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.04181v1-abstract-full').style.display = 'inline'; document.getElementById('2212.04181v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.04181v1-abstract-full" style="display: none;"> BL Lacertae had undergone a series of historical high flux activity over a year, from August 2020 in the optical to VHE $纬$-rays. In this paper, we report on optical flux and spectral variability of the first historical maxima outburst event during October-November in g, r and i bands with the 1.26m telescope at Xinglong observatory, China. We detected significant intranight variations with amplitude rising up to $\sim 30$%, when the fastest variability timescale is found to be a few tens of minutes, giving an emitting region size of the order $10^{-3}$ pc, which corresponds to $\sim 100$ Schwarzschild radius of the central black hole, likely coming from some jet mini-structures. Unlike on intranight timescale, a clear frequency dependent pattern along with symmetric timescales ($\sim$ 11d) of flux variation are detected on long timescale. The spectral evolution was predominated by flattening of the spectra with increasing brightness i.e., a bluer-when-brighter trend in 96% of the cases. On the night before the outburst peak, the color indices clustered in two distinct branches in color--magnitude diagram within a period of $\sim$ 6 hours that is connected to a hard-soft-hard spectral evolution trend extracted from time-resolved spectra. Such trend has never seen in BL Lac or any other blazars before to the best of our knowledge. The results obtained in this study can be explained in the context of shock induced particle acceleration or magnetic re-connection in the jet where turbulent processes most likely resulted the asymmetric flux variation on nightly timescale. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.04181v1-abstract-full').style.display = 'none'; document.getElementById('2212.04181v1-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 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">15 pages, 3 tables, 8 figures. Accepted for publication in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.13493">arXiv:2209.13493</a> <span> [<a href="https://arxiv.org/pdf/2209.13493">pdf</a>, <a href="https://arxiv.org/ps/2209.13493">ps</a>, <a href="https://arxiv.org/format/2209.13493">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1093/mnrasl/slac117">10.1093/mnrasl/slac117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigation of a likely orbital periodicity of Nova Hercules 2021 in X-rays and gamma-rays </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lin%2C+L+C">Lupin Chun-Che Lin</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jhih-Ling Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+C">Chin-Ping Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Takata%2C+J">Jumpei Takata</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+K">Kwan-Lok 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="2209.13493v1-abstract-short" style="display: inline;"> We report a detection of a 0.153 days period in the classical nova V1674 Her using the NICER observations taken within a month since the outburst (i.e., about MJD 59405). The X-ray period is consistent with the orbital period previously found in the optical band, strongly suggesting the NICER signal as the X-ray orbital periodicity of the system. A seemingly double-humped profile was obtained by f… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.13493v1-abstract-full').style.display = 'inline'; document.getElementById('2209.13493v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.13493v1-abstract-full" style="display: none;"> We report a detection of a 0.153 days period in the classical nova V1674 Her using the NICER observations taken within a month since the outburst (i.e., about MJD 59405). The X-ray period is consistent with the orbital period previously found in the optical band, strongly suggesting the NICER signal as the X-ray orbital periodicity of the system. A seemingly double-humped profile was obtained by folding the detrended X-ray light curve with the period after removing the rotational X-ray pulsations of the nova. The profile may be caused by occultation by the companion or the accretion disk, possibly indicating a high inclination of the system. The gamma-ray emission of V1674 Her with a significance level > 5 sigma was detected by Fermi-LAT close to its optical peak and the emission faded away within 1 day, which is the shortest duration known for a gamma-ray nova. Folded on 0.153days, a marginal gamma-ray variability can be also seen in the LAT light curve, but without the double-hump feature observed in X-rays. If the gamma-ray modulation is real, its origin is probably different from that observed in the X-ray and optical bands. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.13493v1-abstract-full').style.display = 'none'; document.getElementById('2209.13493v1-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> 27 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">5 pages and 5 figures, accepted by MNRAS letter</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.09908">arXiv:2209.09908</a> <span> [<a href="https://arxiv.org/pdf/2209.09908">pdf</a>, <a href="https://arxiv.org/format/2209.09908">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 Physics - Phenomenology">hep-ph</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/10.1103/PhysRevLett.130.241001">10.1103/PhysRevLett.130.241001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Opening up a window on the postinflationary QCD axion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y">Yunjia Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng 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="2209.09908v2-abstract-short" style="display: inline;"> The QCD axion cosmology depends crucially on whether the QCD axion is present during inflation or not. We point out that contrary to the standard criterion, the Peccei-Quinn (PQ) symmetry could remain unbroken during inflation, even when the axion decay constant, $f_a$, is (much) above the inflationary Hubble scale, $H_I$. This is achieved through the heavy-lifting of the PQ scalar field due to it… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.09908v2-abstract-full').style.display = 'inline'; document.getElementById('2209.09908v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.09908v2-abstract-full" style="display: none;"> The QCD axion cosmology depends crucially on whether the QCD axion is present during inflation or not. We point out that contrary to the standard criterion, the Peccei-Quinn (PQ) symmetry could remain unbroken during inflation, even when the axion decay constant, $f_a$, is (much) above the inflationary Hubble scale, $H_I$. This is achieved through the heavy-lifting of the PQ scalar field due to its leading non-renormalizable interaction with the inflaton, encoded in a high-dimensional operator which respects the approximate shift symmetry of the inflaton. The mechanism opens up a new window for the post-inflationary QCD axion and significantly enlarges the parameter space, in which the QCD axion dark matter with $f_a > H_I$ could be compatible with high-scale inflation and free from constraints on axion isocurvature perturbations. There also exist non-derivative couplings, which still keep the inflaton shift symmetry breaking under control, to achieve the heavy-lifting of the PQ field during inflation. Additionally, by introducing an early matter domination era, more parameter space of high $f_a$ could yield the observed DM abundance. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.09908v2-abstract-full').style.display = 'none'; document.getElementById('2209.09908v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">v1: 9 pages, 1 figure; v2: PRL version, 10 pages, 1 figure, references added, discussions expanded, main conclusions unchanged</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Lett. 130, 241001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.12917">arXiv:2208.12917</a> <span> [<a href="https://arxiv.org/pdf/2208.12917">pdf</a>, <a href="https://arxiv.org/format/2208.12917">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> </div> <p class="title is-5 mathjax"> The Classification of Blazars Candidates of Uncertain Types </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Jun-Hui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+K">Ke-Yin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hu-Bing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+W">Wen-Xin Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Liang%2C+J">Jing-Chao Liang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+G">Guo-Hai Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Yang%2C+J">Jiang-He Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Yuan%2C+Y">Yu-Hai Yuan</a>, <a href="/search/astro-ph?searchtype=author&query=Wu%2C+D">De-Xiang Wu</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2208.12917v1-abstract-short" style="display: inline;"> In this work, the support vector machine (SVM) method is adopted to separate BL Lacertae objects (BL Lacs) and flat spectrum radio quasars (FSRQs) in the plots of photon spectrum index against the photon flux, $伪_{\rm ph} \sim {\rm log}\,F$, that of photon spectrum index against the variability index, $伪_{\rm ph} \sim {\rm log}\, \textit{V\!I}$, and that of variability index against the photon flu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.12917v1-abstract-full').style.display = 'inline'; document.getElementById('2208.12917v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.12917v1-abstract-full" style="display: none;"> In this work, the support vector machine (SVM) method is adopted to separate BL Lacertae objects (BL Lacs) and flat spectrum radio quasars (FSRQs) in the plots of photon spectrum index against the photon flux, $伪_{\rm ph} \sim {\rm log}\,F$, that of photon spectrum index against the variability index, $伪_{\rm ph} \sim {\rm log}\, \textit{V\!I}$, and that of variability index against the photon flux, ${\rm log}\,{V\!I} \sim {\rm log}\,F$. Then we used the dividing lines to tell BL Lacs from FSRQs in the blazars candidates of uncertain types from \textit{Fermi}/LAT catalogue. Our main conclusions are: 1. We separate BL Lacs and FSRQs by $伪_{\rm ph} = -0.123\,{\rm log}\,F + 1.170$ in the $伪_{\rm ph} \sim {\rm log}\,F$ plot, $伪_{\rm ph} = -0.161\,{\rm log}\,{V\!I} + 2.594$ in the $伪_{\rm ph} \sim {\rm log}\,{V\!I}$ plot, and ${\rm log}\,{V\!I} = 0.792\,{\rm log}\,F + 9.203$ in the ${\rm log}\,{V\!I} \sim {\rm log}\,F$ plot. 2. We obtained 932 BL Lac candidates and possible BL Lac candidates, and 585 FSRQ candidates and possible FSRQ candidates. 3. Some discussions are given for comparisons with those in literature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.12917v1-abstract-full').style.display = 'none'; document.getElementById('2208.12917v1-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 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 to 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/2208.10104">arXiv:2208.10104</a> <span> [<a href="https://arxiv.org/pdf/2208.10104">pdf</a>, <a href="https://arxiv.org/format/2208.10104">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac887f">10.3847/1538-4357/ac887f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> An extensive study of blazar broad emission line: Changing-look blazars and Baldwin effect </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Xiao%2C+H">Hubing Xiao</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Ouyang%2C+Z">Zhihao Ouyang</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+L">Liangjun Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+G">Guohai Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Fu%2C+L">Liping Fu</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+S">Shaohua Zhang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2208.10104v1-abstract-short" style="display: inline;"> It is known that the blazar jet emissions are dominated by non-thermal radiation while the accretion disk jets are normally dominated by thermal emission. In this work, our aim is to study the connection between the two types of emission by investigating the correlation between the blazar emission line intensity property, which embodies the nature of accretion disk, and the $纬$-ray flux property,… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10104v1-abstract-full').style.display = 'inline'; document.getElementById('2208.10104v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.10104v1-abstract-full" style="display: none;"> It is known that the blazar jet emissions are dominated by non-thermal radiation while the accretion disk jets are normally dominated by thermal emission. In this work, our aim is to study the connection between the two types of emission by investigating the correlation between the blazar emission line intensity property, which embodies the nature of accretion disk, and the $纬$-ray flux property, which is the representative of jet emission. We compiled a sample of 656 blazars with available emission line equivalent widths ($EW$), the GeV $纬$-ray flux, and the SED information from the literature. In this work, we found 55 previous BCUs are now identified as FSRQs, and found 52 Changing-look blazars based on their $EW$ and 45 of them are newly confirmed. These Changing-look blazars have a larger accretion ratio (${\dot M}/{\dot M}_{\rm Edd}$) than BL Lac objects. In addition, we suggest that the lower synchrotron peak blazars (LSPs) could be the source of Changing-look blazars because 90.7\% of the Changing-look blazars in this work are confirmed as LSPs. An anti-correlation between $EW$ and continuum intensity, the so-called global Baldwin effect (BEff) has been confirmed. We suggest the steeper global BEff observed for blazar than for radio-quiet active galactic nuclei (RQ-AGNs) is caused by the inverse Compton scattering of broad-emission-line photons. This interpretation is further supported by the positive correlation between the emission line $EW$ and intrinsic inverse Compton luminosity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.10104v1-abstract-full').style.display = 'none'; document.getElementById('2208.10104v1-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 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 to ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.13709">arXiv:2207.13709</a> <span> [<a href="https://arxiv.org/pdf/2207.13709">pdf</a>, <a href="https://arxiv.org/format/2207.13709">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 Physics - Phenomenology">hep-ph</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="Earth and Planetary Astrophysics">astro-ph.EP</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="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/10.1007/JHEP10(2022)186">10.1007/JHEP10(2022)186 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Jupiter missions as probes of dark matter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Li%2C+L">Lingfeng Li</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">JiJi Fan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.13709v2-abstract-short" style="display: inline;"> Jupiter, the fascinating largest planet in the solar system, has been visited by nine spacecraft, which have collected a significant amount of data about Jovian properties. In this paper, we show that one type of the in situ measurements on the relativistic electron fluxes could be used to probe dark matter (DM) and dark mediator between the dark sector and our visible world. Jupiter, with its imm… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13709v2-abstract-full').style.display = 'inline'; document.getElementById('2207.13709v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.13709v2-abstract-full" style="display: none;"> Jupiter, the fascinating largest planet in the solar system, has been visited by nine spacecraft, which have collected a significant amount of data about Jovian properties. In this paper, we show that one type of the in situ measurements on the relativistic electron fluxes could be used to probe dark matter (DM) and dark mediator between the dark sector and our visible world. Jupiter, with its immense weight and cool core, could be an ideal capturer for DM with masses around the GeV scale. The captured DM particles could annihilate into long-lived dark mediators such as dark photons, which subsequently decay into electrons and positrons outside Jupiter. The charged particles, trapped by the Jovian magnetic field, have been measured in Jupiter missions such as the Galileo probe and the Juno orbiter. We use the data available to set upper bounds on the cross section of DM scattering off nucleons, $蟽_{蠂n}$, for dark mediators with lifetime of order ${\cal O}(0.1-1)$s. The results show that data from Jupiter missions already probe regions in the parameter space un- or under-explored by existing DM searches, e.g., constrain $蟽_{蠂n}$ of order $(10^{-40} - 10^{-38})$ cm$^2$ for 1 GeV DM dominantly annihilating into $e^+e^-$ through dark mediators. This study serves as an example and an initial step to explore the full physics potential of the large planetary datasets from Jupiter missions. We also outline several other potential directions related to secondary products of electrons, positron signals and solar axions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13709v2-abstract-full').style.display = 'none'; document.getElementById('2207.13709v2-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 27 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">34 pages, 10 figures; minor modifications and references added; major conclusion unchanged</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.13058">arXiv:2207.13058</a> <span> [<a href="https://arxiv.org/pdf/2207.13058">pdf</a>, <a href="https://arxiv.org/ps/2207.13058">ps</a>, <a href="https://arxiv.org/format/2207.13058">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1088/1538-3873/ac80d3">10.1088/1538-3873/ac80d3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Constraining the $纬$-ray Emission Region for Fermi-Detected FSRQs by the Seed Photon Approach </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Huang%2C+D">Danyi Huang</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+Z">Ziyan Li</a>, <a href="/search/astro-ph?searchtype=author&query=Liao%2C+J">Jiru Liao</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+X">Xiulin Huang</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+C">Chengfeng Li</a>, <a href="/search/astro-ph?searchtype=author&query=Qian%2C+Y">Yanjun Qian</a>, <a href="/search/astro-ph?searchtype=author&query=Pei%2C+Z">Zhiyuan Pei</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+J">Junhui Fan</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.13058v1-abstract-short" style="display: inline;"> The location of $纬$-ray emitting region in blazars has been an open issue for several decades and is still being debated. We use the Paliya et al. sample of 619 $纬$-ray-loud flat-spectrum radio quasars with the available spectral energy distributions, and employ a seed photon factor approach, to locate the $纬$-rays production region. This method efficiently set up a relation between the peak frequ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13058v1-abstract-full').style.display = 'inline'; document.getElementById('2207.13058v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.13058v1-abstract-full" style="display: none;"> The location of $纬$-ray emitting region in blazars has been an open issue for several decades and is still being debated. We use the Paliya et al. sample of 619 $纬$-ray-loud flat-spectrum radio quasars with the available spectral energy distributions, and employ a seed photon factor approach, to locate the $纬$-rays production region. This method efficiently set up a relation between the peak frequencies and luminosities for the synchrotron emission and inverse Compton scattering, together with a combination of the energy density and characteristic energy for the external seed photon field, namely, $\sqrt{U_0}/蔚_0$, an indicative factor of seed photons (SF) in units of Gauss. By means of comparing it with canonical values of broad-line region and molecular dusty torus, we principally ascertain that the GeV emission is originated far beyond the BLR and close to the DT -- farther out at pc scales from the central black hole, which supports a {\it far-site} scenario for $纬$-ray blazars. We probe the idea that inverse Compton scattering of infrared seed photons is happening in the Thomson regime. This approach and our findings are based on the validity of the External Compton model, which is applicable to understand the GeV emission mechanism in FSRQs. However, the completeness of this framework has been challenged by reports of neutrino emission from blazars. Thus we also shed new light on the neutrino production region by using our derived results since blazars are promising neutrino emitters. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.13058v1-abstract-full').style.display = 'none'; document.getElementById('2207.13058v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in PASP</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2207.12601">arXiv:2207.12601</a> <span> [<a href="https://arxiv.org/pdf/2207.12601">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</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/10.1088/1674-1137/ac9371">10.1088/1674-1137/ac9371 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Flux Variations of Cosmic Ray Air Showers Detected by LHAASO-KM2A During a Thunderstorm on 10 June 2021 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=LHAASO+Collaboration"> LHAASO Collaboration</a>, <a href="/search/astro-ph?searchtype=author&query=Aharonian%2C+F">F. Aharonian</a>, <a href="/search/astro-ph?searchtype=author&query=An%2C+Q">Q. An</a>, <a href="/search/astro-ph?searchtype=author&query=Axikegu"> Axikegu</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+L+X">L. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bai%2C+Y+X">Y. X. Bai</a>, <a href="/search/astro-ph?searchtype=author&query=Bao%2C+Y+W">Y. W. Bao</a>, <a href="/search/astro-ph?searchtype=author&query=Bastieri%2C+D">D. Bastieri</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+X+J">X. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Bi%2C+Y+J">Y. J. Bi</a>, <a href="/search/astro-ph?searchtype=author&query=Cai%2C+J+T">J. T. Cai</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhe Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+Z">Zhen Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J">J. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chang%2C+J+F">J. F. Chang</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+E+S">E. S. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Liang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+L">Long Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+J">M. J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+M+L">M. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+H">S. H. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+S+Z">S. Z. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+T+L">T. L. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X+J">X. J. Chen</a> , et al. (248 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2207.12601v2-abstract-short" style="display: inline;"> The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during the thunderstorm on 10 June 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with maximum fractional increase of 20%. The variations… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.12601v2-abstract-full').style.display = 'inline'; document.getElementById('2207.12601v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2207.12601v2-abstract-full" style="display: none;"> The Large High Altitude Air Shower Observatory (LHAASO) has three sub-arrays, KM2A, WCDA and WFCTA. The flux variations of cosmic ray air showers were studied by analyzing the KM2A data during the thunderstorm on 10 June 2021. The number of shower events that meet the trigger conditions increases significantly in atmospheric electric fields, with maximum fractional increase of 20%. The variations of trigger rates (increases or decreases) are found to be strongly dependent on the primary zenith angle. The flux of secondary particles increases significantly, following a similar trend with that of the shower events. To better understand the observed behavior, Monte Carlo simulations are performed with CORSIKA and G4KM2A (a code based on GEANT4). We find that the experimental data (in saturated negative fields) are in good agreement with simulations, assuming the presence of a uniform upward electric field of 700 V/cm with a thickness of 1500 m in the atmosphere above the observation level. Due to the acceleration/deceleration and deflection by the atmospheric electric field, the number of secondary particles with energy above the detector threshold is modified, resulting in the changes in shower detection rate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2207.12601v2-abstract-full').style.display = 'none'; document.getElementById('2207.12601v2-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">18 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Chinese Phys. C 47 015001 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.14923">arXiv:2203.14923</a> <span> [<a href="https://arxiv.org/pdf/2203.14923">pdf</a>, <a href="https://arxiv.org/format/2203.14923">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 Physics - Experiment">hep-ex</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="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Axion Dark Matter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Adams%2C+C+B">C. B. Adams</a>, <a href="/search/astro-ph?searchtype=author&query=Aggarwal%2C+N">N. Aggarwal</a>, <a href="/search/astro-ph?searchtype=author&query=Agrawal%2C+A">A. Agrawal</a>, <a href="/search/astro-ph?searchtype=author&query=Balafendiev%2C+R">R. Balafendiev</a>, <a href="/search/astro-ph?searchtype=author&query=Bartram%2C+C">C. Bartram</a>, <a href="/search/astro-ph?searchtype=author&query=Baryakhtar%2C+M">M. Baryakhtar</a>, <a href="/search/astro-ph?searchtype=author&query=Bekker%2C+H">H. Bekker</a>, <a href="/search/astro-ph?searchtype=author&query=Belov%2C+P">P. Belov</a>, <a href="/search/astro-ph?searchtype=author&query=Berggren%2C+K+K">K. K. Berggren</a>, <a href="/search/astro-ph?searchtype=author&query=Berlin%2C+A">A. Berlin</a>, <a href="/search/astro-ph?searchtype=author&query=Boutan%2C+C">C. Boutan</a>, <a href="/search/astro-ph?searchtype=author&query=Bowring%2C+D">D. Bowring</a>, <a href="/search/astro-ph?searchtype=author&query=Budker%2C+D">D. Budker</a>, <a href="/search/astro-ph?searchtype=author&query=Caldwell%2C+A">A. Caldwell</a>, <a href="/search/astro-ph?searchtype=author&query=Carenza%2C+P">P. Carenza</a>, <a href="/search/astro-ph?searchtype=author&query=Carosi%2C+G">G. Carosi</a>, <a href="/search/astro-ph?searchtype=author&query=Cervantes%2C+R">R. Cervantes</a>, <a href="/search/astro-ph?searchtype=author&query=Chakrabarty%2C+S+S">S. S. Chakrabarty</a>, <a href="/search/astro-ph?searchtype=author&query=Chaudhuri%2C+S">S. Chaudhuri</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+T+Y">T. Y. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Cheong%2C+S">S. Cheong</a>, <a href="/search/astro-ph?searchtype=author&query=Chou%2C+A">A. Chou</a>, <a href="/search/astro-ph?searchtype=author&query=Co%2C+R+T">R. T. Co</a>, <a href="/search/astro-ph?searchtype=author&query=Conrad%2C+J">J. Conrad</a>, <a href="/search/astro-ph?searchtype=author&query=Croon%2C+D">D. Croon</a> , et al. (130 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="2203.14923v3-abstract-short" style="display: inline;"> Axions are well-motivated dark matter candidates with simple cosmological production mechanisms. They were originally introduced to solve the strong CP problem, but also arise in a wide range of extensions to the Standard Model. This Snowmass white paper summarizes axion phenomenology and outlines next-generation laboratory experiments proposed to detect axion dark matter. There are vibrant synerg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.14923v3-abstract-full').style.display = 'inline'; document.getElementById('2203.14923v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.14923v3-abstract-full" style="display: none;"> Axions are well-motivated dark matter candidates with simple cosmological production mechanisms. They were originally introduced to solve the strong CP problem, but also arise in a wide range of extensions to the Standard Model. This Snowmass white paper summarizes axion phenomenology and outlines next-generation laboratory experiments proposed to detect axion dark matter. There are vibrant synergies with astrophysical searches and advances in instrumentation including quantum-enabled readout, high-Q resonators and cavities and large high-field magnets. This white paper outlines a clear roadmap to discovery, and shows that the US is well-positioned to be at the forefront of the search for axion dark matter in the coming decade. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.14923v3-abstract-full').style.display = 'none'; document.getElementById('2203.14923v3-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 28 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">restore and expand author list</span> </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" 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