A. V. Glushkov, L. T. Ksenofontov, K. G. Lebedev, A. Sabourov
In this article a new method is proposed for estimating the mass composition of cosmic rays in individual events with energies above $1.25 times 10^{19}$ eV. It is based on a joint analysis of experimental data and simulation results obtained using the QGSJet-II.04 model for muons with threshold energy $E_{mu} = 1.0 times costheta$ GeV in air showers with zenith angles up to 60 degrees. The data from ground-based and underground scintillation detectors of the Yakutsk EAS array were used. Separate groups of nuclei and other primary particles were found.
本文提出了一种新的方法来估计能量超过1.25 times 10^{19}$eV的单个事件中宇宙射线的质量组成。它是在对实验数据和模拟结果进行联合分析的基础上提出来的，模拟结果是使用QGSJet-II.04模型对天顶角达到60度的空气阵列中阈值能量为$E_{mu}= 1.0 times costheta$ GeV的μ介子进行模拟的。使用的数据来自雅库茨克 EAS 阵列的地面和地下闪烁探测器。发现了独立的原子核和其他原初粒子群。
{"title":"Estimation of the composition of ultra-high energy cosmic rays using the muon correlation method based on Yakutsk EAS array data","authors":"A. V. Glushkov, L. T. Ksenofontov, K. G. Lebedev, A. Sabourov","doi":"arxiv-2409.10880","DOIUrl":"https://doi.org/arxiv-2409.10880","url":null,"abstract":"In this article a new method is proposed for estimating the mass composition\u0000of cosmic rays in individual events with energies above $1.25 times 10^{19}$\u0000eV. It is based on a joint analysis of experimental data and simulation results\u0000obtained using the QGSJet-II.04 model for muons with threshold energy $E_{mu}\u0000= 1.0 times costheta$ GeV in air showers with zenith angles up to 60\u0000degrees. The data from ground-based and underground scintillation detectors of\u0000the Yakutsk EAS array were used. Separate groups of nuclei and other primary\u0000particles were found.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have investigated the evolutionary connections of the isolated neutron star (NS) populations including radio pulsars (RPs), anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs), dim isolated NSs (XDINs), ``high-magnetic-field'' RPs (``HBRPs''), central compact objects (CCOs), rotating radio transients (RRATs), and long-period pulsars (LPPs) in the fallback disc model. The model can reproduce these NS families as a natural outcome of different initial conditions (initial period, disc mass, and dipole moment, $mu$) with a continuous $mu$ distribution in the $sim 10^{27} - 5 times 10^{30}$ G cm$^3$ range. Results of our simulations can be summarised as follows: (1) A fraction of ``HBRPs'' with relatively high $mu$ evolve into the persistent AXP/SGR properties, and subsequently become LPPs. (2) Persistent AXP/SGRs do not have evolutionary links with CCOs, XDINs, and RRATs. (3) For a wide range of $mu$, most RRATs evolve passing through RP or ``HBRP'' properties during their early evolutionary phases. (4) A fraction of RRATs which have the highest estimated birth rate seem to be the progenitors of XDINs. (5) LPPs, whose existence was predicted by the fallback disc model, are the sources evolving in the late stage of evolution before the discs become inactive. These results provide concrete support to the ideas proposing evolutionary connections between the NS families to account for the ``birth-rate problem'', the discrepancy between the cumulative birth rate estimated for these systems and the core-collapse supernova rate.
{"title":"Long-term Evolutionary Links Between the Isolated Neutron Star Populations","authors":"Ali Arda Gencali, Unal Ertan","doi":"arxiv-2409.11595","DOIUrl":"https://doi.org/arxiv-2409.11595","url":null,"abstract":"We have investigated the evolutionary connections of the isolated neutron\u0000star (NS) populations including radio pulsars (RPs), anomalous X-ray pulsars\u0000(AXPs), soft gamma repeaters (SGRs), dim isolated NSs (XDINs),\u0000``high-magnetic-field'' RPs (``HBRPs''), central compact objects (CCOs),\u0000rotating radio transients (RRATs), and long-period pulsars (LPPs) in the\u0000fallback disc model. The model can reproduce these NS families as a natural\u0000outcome of different initial conditions (initial period, disc mass, and dipole\u0000moment, $mu$) with a continuous $mu$ distribution in the $sim 10^{27} - 5\u0000times 10^{30}$ G cm$^3$ range. Results of our simulations can be summarised as\u0000follows: (1) A fraction of ``HBRPs'' with relatively high $mu$ evolve into the\u0000persistent AXP/SGR properties, and subsequently become LPPs. (2) Persistent\u0000AXP/SGRs do not have evolutionary links with CCOs, XDINs, and RRATs. (3) For a\u0000wide range of $mu$, most RRATs evolve passing through RP or ``HBRP''\u0000properties during their early evolutionary phases. (4) A fraction of RRATs\u0000which have the highest estimated birth rate seem to be the progenitors of\u0000XDINs. (5) LPPs, whose existence was predicted by the fallback disc model, are\u0000the sources evolving in the late stage of evolution before the discs become\u0000inactive. These results provide concrete support to the ideas proposing\u0000evolutionary connections between the NS families to account for the\u0000``birth-rate problem'', the discrepancy between the cumulative birth rate\u0000estimated for these systems and the core-collapse supernova rate.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
It is generally accepted that all massive galaxies host supermassive black holes (BHs) in their center and that mergers of two galaxies lead to the formation of BH binaries. The most interesting among them comprise the mergers in their final state, that is to say with parsec (3.2 light years) or sub-parsec orbital separations. It is possible to detect these systems with binary self-lensing. Here we report the potential detection of a central supermassive BH binary in the active galaxy (AGN) NGC1566 based on a microlensing outburst. The light curve of the outburst - based on observations with the All Sky Automated Survey for SuperNovae - lasted from the beginning of 2017 until the beginning of 2020. The steep symmetric light curve as well as its shape look very different with respect to normal random variations in AGN. However, the observations could be easily reproduced with a best-fit standard microlensing light curve. Based on the light curve, we derived a characteristic timescale of 155 days. During the outburst, the continuum as well as the broad line intensities varied; however, the narrow emission lines did not. This is an indication that the lensing object orbits the AGN nucleus between the broad line region (BLR) and the narrow line region (NLR), that is, at a distance on the order of 250 light days. The light curve can be reproduced by a lens with a BH mass of 5*10^{5} M_solar. This implies a mass ratio to the central AGN on the order of 1 to 10.
{"title":"Evidence for gravitational self-lensing of the central supermassive black hole binary in the Seyfert galaxy NGC 1566","authors":"Wolfram Kollatschny, Doron Chelouche","doi":"arxiv-2409.11209","DOIUrl":"https://doi.org/arxiv-2409.11209","url":null,"abstract":"It is generally accepted that all massive galaxies host supermassive black\u0000holes (BHs) in their center and that mergers of two galaxies lead to the\u0000formation of BH binaries. The most interesting among them comprise the mergers\u0000in their final state, that is to say with parsec (3.2 light years) or\u0000sub-parsec orbital separations. It is possible to detect these systems with\u0000binary self-lensing. Here we report the potential detection of a central\u0000supermassive BH binary in the active galaxy (AGN) NGC1566 based on a\u0000microlensing outburst. The light curve of the outburst - based on observations\u0000with the All Sky Automated Survey for SuperNovae - lasted from the beginning of\u00002017 until the beginning of 2020. The steep symmetric light curve as well as\u0000its shape look very different with respect to normal random variations in AGN.\u0000However, the observations could be easily reproduced with a best-fit standard\u0000microlensing light curve. Based on the light curve, we derived a characteristic\u0000timescale of 155 days. During the outburst, the continuum as well as the broad\u0000line intensities varied; however, the narrow emission lines did not. This is an\u0000indication that the lensing object orbits the AGN nucleus between the broad\u0000line region (BLR) and the narrow line region (NLR), that is, at a distance on\u0000the order of 250 light days. The light curve can be reproduced by a lens with a\u0000BH mass of 5*10^{5} M_solar. This implies a mass ratio to the central AGN on\u0000the order of 1 to 10.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soumya Shreeram, Johan Comparat, Andrea Merloni, Yi Zhang, Gabriele Ponti, Kirpal Nandra, John ZuHone, Ilaria Marini, Stephan Vladutescu-Zopp, Paola Popesso, Ruediger Pakmor, Riccardo Seppi, Celine Peroux, Daniele Sorini
The hot phase of the circumgalactic medium (CGM) allows us to probe the inflow and outflow of gas within a galaxy, which is responsible for dictating the evolution of the galaxy. Studying the hot CGM sheds light on a better understanding of gas physics, which is crucial to inform and constrain simulation models. With the recent advances in observational measurements probing the hot CGM in X-rays and tSZ, we have a new avenue for widening our knowledge of gas physics and feedback by exploiting the information from current/future observations. In this paper, we use the TNG300 hydrodynamical simulations to build a fully self-consistent forward model for the hot CGM. We construct a lightcone and generate mock X-ray observations. We quantify the projection effects, namely the locally correlated large-scale structure in X-rays and the effect due to satellite galaxies misclassified as centrals which affects the measured hot CGM galactocentric profiles in stacking experiments. We present an analytical model that describes the intrinsic X-ray surface brightness profile across the stellar and halo mass bins. The increasing stellar mass bins result in decreasing values of $beta$, the exponent quantifying the slope of the intrinsic galactocentric profiles. We carry forward the current state-of-the-art by also showing the impact of the locally correlated environment on the measured X-ray surface brightness profiles. We also present, for the first time, the effect of misclassified centrals in stacking experiments for three stellar mass bins: $10^{10.5-11} M_odot$, $10^{11-11.2} M_odot$, and $10^{11.2-11.5} M_odot$. We find that the contaminating effect of the misclassified centrals on the stacked profiles increases when the stellar mass decreases.
环银河介质（CGM）的热相使我们能够探测星系内气体的内流和外流，而气体的内流和外流决定了星系的演化。研究热的环银河介质有助于更好地理解气体物理学，这对提供信息和约束模拟模型至关重要。随着最近用X射线和tSZ对热CGM进行观测测量的进展，我们有了一个新的途径，可以利用当前/未来观测所获得的信息来拓宽我们对气体物理和反馈的认识。在本文中，我们利用 TNG300 流体力学模拟为热 CGM 建立了一个完全自洽的前向模型。我们构建了一个光锥，并生成了模拟 X 射线观测数据。我们量化了投影效应，即X射线中局部相关的大尺度结构，以及卫星星系被误判为中心星系所产生的效应，这些效应影响了堆叠实验中测得的热CGM星系中心剖面。恒星质量越大，$beta$的值就越小，而$beta$是量化本征伽马中心剖面斜率的指数。我们还展示了局部相关环境对测量到的 X 射线表面亮度剖面的影响，从而延续了当前的先进水平。我们还首次提出了在三个恒星质量带：$10^{10.5-11} M_odot$、$10^{11-11.2} M_odot$和$10^{11.2-11.5} M_odot$的堆叠实验中，被错误分类的中心点的影响。我们发现，当恒星质量减小时，错误分类的中心点对堆叠剖面的污染效应会增大。
{"title":"Quantifying Observational Projection Effects with a Simulation-based hot CGM model","authors":"Soumya Shreeram, Johan Comparat, Andrea Merloni, Yi Zhang, Gabriele Ponti, Kirpal Nandra, John ZuHone, Ilaria Marini, Stephan Vladutescu-Zopp, Paola Popesso, Ruediger Pakmor, Riccardo Seppi, Celine Peroux, Daniele Sorini","doi":"arxiv-2409.10397","DOIUrl":"https://doi.org/arxiv-2409.10397","url":null,"abstract":"The hot phase of the circumgalactic medium (CGM) allows us to probe the\u0000inflow and outflow of gas within a galaxy, which is responsible for dictating\u0000the evolution of the galaxy. Studying the hot CGM sheds light on a better\u0000understanding of gas physics, which is crucial to inform and constrain\u0000simulation models. With the recent advances in observational measurements\u0000probing the hot CGM in X-rays and tSZ, we have a new avenue for widening our\u0000knowledge of gas physics and feedback by exploiting the information from\u0000current/future observations. In this paper, we use the TNG300 hydrodynamical\u0000simulations to build a fully self-consistent forward model for the hot CGM. We\u0000construct a lightcone and generate mock X-ray observations. We quantify the\u0000projection effects, namely the locally correlated large-scale structure in\u0000X-rays and the effect due to satellite galaxies misclassified as centrals which\u0000affects the measured hot CGM galactocentric profiles in stacking experiments.\u0000We present an analytical model that describes the intrinsic X-ray surface\u0000brightness profile across the stellar and halo mass bins. The increasing\u0000stellar mass bins result in decreasing values of $beta$, the exponent\u0000quantifying the slope of the intrinsic galactocentric profiles. We carry\u0000forward the current state-of-the-art by also showing the impact of the locally\u0000correlated environment on the measured X-ray surface brightness profiles. We\u0000also present, for the first time, the effect of misclassified centrals in\u0000stacking experiments for three stellar mass bins: $10^{10.5-11} M_odot$,\u0000$10^{11-11.2} M_odot$, and $10^{11.2-11.5} M_odot$. We find that the\u0000contaminating effect of the misclassified centrals on the stacked profiles\u0000increases when the stellar mass decreases.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Keerthi Kunnumkai, Antonella Palmese, Mattia Bulla, Tim Dietrich, Amanda M. Farah, Peter T. H. Pang
The detection of the gravitational-wave event GW230529, presumably a neutron star-black hole (NSBH) merger, by the LIGO-Virgo-KAGRA (LVK) Collaboration is an exciting discovery for multimessenger astronomy. The black hole (BH) has a high probability of falling within the ''mass gap'' between the peaks of the neutron star (NS) and the BH mass distributions. Because of the low primary mass, the binary is more likely to produce an electromagnetic counterpart than previously detected NSBH mergers. We investigate the possible kilonova (KN) emission from GW230529, and find that if it was an NSBH, there is a $sim$ 2-41% probability (depending on the assumed equation of state) that GW230925 produced a KN with magnitude peaking at $sim 1-2$ day post merger at $g lesssim 23.5$, $i<23$. Hence, it could have been detected by ground-based telescopes. If it was a binary neutron star (BNS) merger, we find $sim$ 0-12% probability that it produced a KN. Motivated by these numbers, we simulated a broader population of mgNSBH mergers that may be detected in O4, and we obtained a 9-21% chance of producing a KN, which would be detectable with $glesssim 25$ and $ i lesssim 24$, typically fainter than what is expected from GW230529. Based on these findings, DECam-like instruments may be able to detect up to 80% of future mgNSBH KNe, thus up to $sim1$ multimessenger mgNSBH per year may be discoverable at the current level of sensitivity (O4).
{"title":"Kilonova emission from GW230529 and mass gap neutron star-black hole mergers","authors":"Keerthi Kunnumkai, Antonella Palmese, Mattia Bulla, Tim Dietrich, Amanda M. Farah, Peter T. H. Pang","doi":"arxiv-2409.10651","DOIUrl":"https://doi.org/arxiv-2409.10651","url":null,"abstract":"The detection of the gravitational-wave event GW230529, presumably a neutron\u0000star-black hole (NSBH) merger, by the LIGO-Virgo-KAGRA (LVK) Collaboration is\u0000an exciting discovery for multimessenger astronomy. The black hole (BH) has a\u0000high probability of falling within the ''mass gap'' between the peaks of the\u0000neutron star (NS) and the BH mass distributions. Because of the low primary\u0000mass, the binary is more likely to produce an electromagnetic counterpart than\u0000previously detected NSBH mergers. We investigate the possible kilonova (KN)\u0000emission from GW230529, and find that if it was an NSBH, there is a $sim$\u00002-41% probability (depending on the assumed equation of state) that GW230925\u0000produced a KN with magnitude peaking at $sim 1-2$ day post merger at $g\u0000lesssim 23.5$, $i<23$. Hence, it could have been detected by ground-based\u0000telescopes. If it was a binary neutron star (BNS) merger, we find $sim$ 0-12%\u0000probability that it produced a KN. Motivated by these numbers, we simulated a\u0000broader population of mgNSBH mergers that may be detected in O4, and we\u0000obtained a 9-21% chance of producing a KN, which would be detectable with\u0000$glesssim 25$ and $ i lesssim 24$, typically fainter than what is expected\u0000from GW230529. Based on these findings, DECam-like instruments may be able to\u0000detect up to 80% of future mgNSBH KNe, thus up to $sim1$ multimessenger mgNSBH\u0000per year may be discoverable at the current level of sensitivity (O4).","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
David L. Moutard, Renee M. Ludlam, Edward M. Cackett, Javier A. García, Jon M. Miller, Dan R. Wilkins
In this study, we examine 51 archival NICER observations and 6 archival NuSTAR observations of the neutron star (NS) ultra-compact X-ray binary (UCXB) 4U 0614+091, which span over 5 years. The source displays persistent reflection features, so we use a reflection model designed for UCXBs, with overabundant carbon and oxygen ({sc xillverCO}) to study how various components of the system vary over time. The flux of this source is known to vary quasi-periodically on a timescale of a few days, so we study how the various model components change as the overall flux varies. The flux of most components scales linearly with the overall flux, while the power law, representing coronal emission, is anti-correlated as expected. This is consistent with previous studies of the source. We also find that during observations of the high-soft state, the disk emissivity profile as a function of radius becomes steeper. We interpret this as the corona receding to be closer to the compact object during these states, at which point the assumed power law illumination of {sc xillverCO} may be inadequate to describe the illumination of the disk.
{"title":"A View of the Long-Term Spectral Behavior of Ultra Compact X-Ray Binary 4U 0614+091","authors":"David L. Moutard, Renee M. Ludlam, Edward M. Cackett, Javier A. García, Jon M. Miller, Dan R. Wilkins","doi":"arxiv-2409.10279","DOIUrl":"https://doi.org/arxiv-2409.10279","url":null,"abstract":"In this study, we examine 51 archival NICER observations and 6 archival\u0000NuSTAR observations of the neutron star (NS) ultra-compact X-ray binary (UCXB)\u00004U 0614+091, which span over 5 years. The source displays persistent reflection\u0000features, so we use a reflection model designed for UCXBs, with overabundant\u0000carbon and oxygen ({sc xillverCO}) to study how various components of the\u0000system vary over time. The flux of this source is known to vary\u0000quasi-periodically on a timescale of a few days, so we study how the various\u0000model components change as the overall flux varies. The flux of most components\u0000scales linearly with the overall flux, while the power law, representing\u0000coronal emission, is anti-correlated as expected. This is consistent with\u0000previous studies of the source. We also find that during observations of the\u0000high-soft state, the disk emissivity profile as a function of radius becomes\u0000steeper. We interpret this as the corona receding to be closer to the compact\u0000object during these states, at which point the assumed power law illumination\u0000of {sc xillverCO} may be inadequate to describe the illumination of the disk.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pragati Sahu, Swadesh Chand, Parijat Thakur, G. C. Dewangan, V. K. Agrawal, Prakash Tripathi, Subhashish Das
We perform a comprehensive timing and broadband spectral analysis using an AstroSat observation of the low-mass black hole X-ray binary H~1743--322 during 2017 outburst. Additionally, we use two Swift/XRT observations, one of which is simultaneous with AstroSat and the other taken three days earlier, for timing analysis. The hardness-intensity diagram indicates that the 2017 outburst was a failed one unlike the previous successful outburst in 2016. We detect type C quasi-periodic oscillation (QPO) in the simultaneous AstroSat and Swift/XRT observations at $sim0.4$ Hz, whereas an upper harmonic is noticed at $sim0.9$ Hz in the AstroSat data only. Although these features are found to be energy independent, we notice a shift of $sim0.08$ Hz in the QPO frequency over the interval of three days. We also investigate the nature of variability in the two consecutive failed outbursts in 2017 and 2018. We detect soft time lags of $23.2pm12.2$ ms and $140pm80$ ms at the type C QPO frequencies in 2017 Astrosat and 2018 XMM-Newton data, respectively. The lag-energy spectra from both the outbursts suggest that the soft lags may be associated with the reflection features. The broadband spectral analysis indicates that the source was in the low/hard state during our AstroSat observation. Modeling of the disk and reflection continuum suggests the presence of a significantly truncated accretion disk by at least $27.4~r_{rm{g}}$ from the ISCO when the source luminosity is $sim1.6%$ of the Eddington luminosity.
{"title":"2017 Outburst of H 1743-322: AstroSat and Swift View","authors":"Pragati Sahu, Swadesh Chand, Parijat Thakur, G. C. Dewangan, V. K. Agrawal, Prakash Tripathi, Subhashish Das","doi":"arxiv-2409.10253","DOIUrl":"https://doi.org/arxiv-2409.10253","url":null,"abstract":"We perform a comprehensive timing and broadband spectral analysis using an\u0000AstroSat observation of the low-mass black hole X-ray binary H~1743--322 during\u00002017 outburst. Additionally, we use two Swift/XRT observations, one of which is\u0000simultaneous with AstroSat and the other taken three days earlier, for timing\u0000analysis. The hardness-intensity diagram indicates that the 2017 outburst was a\u0000failed one unlike the previous successful outburst in 2016. We detect type C\u0000quasi-periodic oscillation (QPO) in the simultaneous AstroSat and Swift/XRT\u0000observations at $sim0.4$ Hz, whereas an upper harmonic is noticed at $sim0.9$\u0000Hz in the AstroSat data only. Although these features are found to be energy\u0000independent, we notice a shift of $sim0.08$ Hz in the QPO frequency over the\u0000interval of three days. We also investigate the nature of variability in the\u0000two consecutive failed outbursts in 2017 and 2018. We detect soft time lags of\u0000$23.2pm12.2$ ms and $140pm80$ ms at the type C QPO frequencies in 2017\u0000Astrosat and 2018 XMM-Newton data, respectively. The lag-energy spectra from\u0000both the outbursts suggest that the soft lags may be associated with the\u0000reflection features. The broadband spectral analysis indicates that the source\u0000was in the low/hard state during our AstroSat observation. Modeling of the disk\u0000and reflection continuum suggests the presence of a significantly truncated\u0000accretion disk by at least $27.4~r_{rm{g}}$ from the ISCO when the source\u0000luminosity is $sim1.6%$ of the Eddington luminosity.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Olivier Gilbert, John J. Ruan, Michael Eracleous, Daryl Haggard, Jessie C. Runnoe
The physical processes that produce X-ray Quasi-Periodic Eruptions (QPEs) recently discovered from the nuclei of several low-redshift galaxies are mysterious. Several pieces of observational evidence strongly suggest a link between QPEs and Tidal Disruption Events (TDE). Previous studies also reveal that the morphologies of TDE host galaxies are highly concentrated, with high Sersic indicies, bulge-to-total light (B/T) ratios, and stellar surface mass densities relative to the broader galaxy population. We use these distinctive properties to test the link between QPEs and TDEs, by comparing these parameters of QPE host galaxies to TDE host galaxies. We employ archival Legacy Survey images of a sample of 9 QPE host galaxies and a sample of 13 TDE host galaxies, and model their surface brightness profiles. We show that QPE host galaxies have high Sersic indices of ~3, high B/T ratios of ~0.5, and high surface mass densities of ~10^10 Msun kpc^-2. These properties are similar to TDE host galaxies, but are in strong contrast to a mass- and redshift-matched control sample of galaxies. We also find tentative evidence that the central black holes in both QPE and TDE host galaxies are undermassive relative to their stellar mass. The morphological similarities between QPE and TDE host galaxies at the population level add to the mounting evidence of a physical link between these phenomena, and favor QPE models that also invoke TDEs.
{"title":"A Host Galaxy Morphology Link Between Quasi-Periodic Eruptions and Tidal Disruption Events","authors":"Olivier Gilbert, John J. Ruan, Michael Eracleous, Daryl Haggard, Jessie C. Runnoe","doi":"arxiv-2409.10486","DOIUrl":"https://doi.org/arxiv-2409.10486","url":null,"abstract":"The physical processes that produce X-ray Quasi-Periodic Eruptions (QPEs)\u0000recently discovered from the nuclei of several low-redshift galaxies are\u0000mysterious. Several pieces of observational evidence strongly suggest a link\u0000between QPEs and Tidal Disruption Events (TDE). Previous studies also reveal\u0000that the morphologies of TDE host galaxies are highly concentrated, with high\u0000Sersic indicies, bulge-to-total light (B/T) ratios, and stellar surface mass\u0000densities relative to the broader galaxy population. We use these distinctive\u0000properties to test the link between QPEs and TDEs, by comparing these\u0000parameters of QPE host galaxies to TDE host galaxies. We employ archival Legacy\u0000Survey images of a sample of 9 QPE host galaxies and a sample of 13 TDE host\u0000galaxies, and model their surface brightness profiles. We show that QPE host\u0000galaxies have high Sersic indices of ~3, high B/T ratios of ~0.5, and high\u0000surface mass densities of ~10^10 Msun kpc^-2. These properties are similar to\u0000TDE host galaxies, but are in strong contrast to a mass- and redshift-matched\u0000control sample of galaxies. We also find tentative evidence that the central\u0000black holes in both QPE and TDE host galaxies are undermassive relative to\u0000their stellar mass. The morphological similarities between QPE and TDE host\u0000galaxies at the population level add to the mounting evidence of a physical\u0000link between these phenomena, and favor QPE models that also invoke TDEs.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Extreme-mass ratio inspirals (EMRIs) of stellar-mass black holes (BHs) are among the main targets for upcoming low-frequency gravitational wave (GW) detectors such as the Laser Interferometer Space Antenna (LISA). In the classical scenario, EMRIs are formed when BHs scatter off each other and are driven onto highly eccentric orbits that gradually inspiral due to GW emission. If the cluster is in a state of strong mass segregation, the BHs are expected to reside in a steep cusp around the central massive black hole (MBH), which would facilitate more efficient EMRI formation. However, strong mass segregation may also lead to an increased rate of ejections due to close encounters between the BHs. Here, we test the relevance of such ejections for EMRI formation by numerically solving a two-dimensional Fokker-Planck equation. Our formalism includes the effects of two-body relaxation, GW dissipation, and ejections. We find that the EMRI formation rate can be suppressed due to ejections by more than an order of magnitude for strongly segregated BH cusps with density index $gammagtrsim 2.25$ around central MBHs of mass $M_{bullet} lesssim 10^6 M_odot $. The EMRI formation rate levels off up to a maximum value of $simeq 200~{rm Gyr}^{-1}$ due to ejections, which is roughly an order of magnitude lower than the usual scenarios ignoring ejections for steep BH cusps around low mass MBHs. Our analysis brings forth the significance of strong scatterings for EMRI formation in galactic nuclei.
{"title":"Extreme-mass ratio inspirals in strong segregation regime -- to inspiral or to get ejected?","authors":"Karamveer Kaur, Hagai Perets","doi":"arxiv-2409.10618","DOIUrl":"https://doi.org/arxiv-2409.10618","url":null,"abstract":"Extreme-mass ratio inspirals (EMRIs) of stellar-mass black holes (BHs) are\u0000among the main targets for upcoming low-frequency gravitational wave (GW)\u0000detectors such as the Laser Interferometer Space Antenna (LISA). In the\u0000classical scenario, EMRIs are formed when BHs scatter off each other and are\u0000driven onto highly eccentric orbits that gradually inspiral due to GW emission.\u0000If the cluster is in a state of strong mass segregation, the BHs are expected\u0000to reside in a steep cusp around the central massive black hole (MBH), which\u0000would facilitate more efficient EMRI formation. However, strong mass\u0000segregation may also lead to an increased rate of ejections due to close\u0000encounters between the BHs. Here, we test the relevance of such ejections for\u0000EMRI formation by numerically solving a two-dimensional Fokker-Planck equation.\u0000Our formalism includes the effects of two-body relaxation, GW dissipation, and\u0000ejections. We find that the EMRI formation rate can be suppressed due to\u0000ejections by more than an order of magnitude for strongly segregated BH cusps\u0000with density index $gammagtrsim 2.25$ around central MBHs of mass\u0000$M_{bullet} lesssim 10^6 M_odot $. The EMRI formation rate levels off up to\u0000a maximum value of $simeq 200~{rm Gyr}^{-1}$ due to ejections, which is\u0000roughly an order of magnitude lower than the usual scenarios ignoring ejections\u0000for steep BH cusps around low mass MBHs. Our analysis brings forth the\u0000significance of strong scatterings for EMRI formation in galactic nuclei.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260107","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eunyu LeeDepartment of Physics, College of Natural Sciences, UNIST, Korea, Dongsu RyuDepartment of Physics, College of Natural Sciences, UNIST, Korea, Hyesung KangDepartment of Earth Sciences, Pusan National University, Korea
In a binary merger of two subclusters with comparable masses, a pair of merger shocks are typically generated, often manifesting as double radio relics. Using cosmological hydrodynamic simulations, we identify major merger events with mass ratio $mathcal{M}_1/mathcal{M}_2lesssim4$ and impact parameter $b/r_{rm vir,1}lesssim1$, where $r_{rm vir,1}$ is the virial radius of the larger subcluster. We analyze merger shock surfaces approximately 1 Gyr after the pericenter passage, focusing on their morphology and the distribution of the Mach number, $M_s$, of their constituent shock zones. The shock surfaces exhibit an elongated shape with a minor-to-major axis ratio of $sim0.6-0.9$ and cover the area of $sim5-20%$ of the enclosed sphere. The area ratio of the two shock surfaces roughly scales with $mathcal{M}_1/mathcal{M}_2$, typically positioning the larger shock ahead of the smaller subcluster. The axis connecting the two subclusters generally does not pass through the centers of the shock surfaces, due to the nonzero impact parameter and the turbulent flows around them. The distribution of $M_s$ of shock zones on each surface can be approximated by a log-normal function, peaking at $M_{s,rm{peak}}approx2-4.5$ and extending up to $sim10$. The surface-area-weighted and X-ray-emissivity-weighted average Mach numbers are comparable, with ${langle{M_s}rangle}_{rm{area}}approx2.3-4.4$ and ${langle{M_s}rangle}_{X}approx2-4$. In contrast, the cosmic-ray-energy-flux-weighted average Mach numbers are higher with ${langle{M_s}rangle}_{rm{CR}}approx3-5$. This discrepancy aligns with the differences between Mach numbers derived from X-ray and radio observations of radio relic shocks. On the other hand, we find that mostly ${langle{M_s}rangle}_{X}gtrsim2$ for simulated merger shocks, although shocks with $M_{rm X-ray}lesssim2$ are often reported in observations.
{"title":"Morphology and Mach Number Distribution of Merger Shock Surfaces in Merging Galaxy Clusters","authors":"Eunyu LeeDepartment of Physics, College of Natural Sciences, UNIST, Korea, Dongsu RyuDepartment of Physics, College of Natural Sciences, UNIST, Korea, Hyesung KangDepartment of Earth Sciences, Pusan National University, Korea","doi":"arxiv-2409.09924","DOIUrl":"https://doi.org/arxiv-2409.09924","url":null,"abstract":"In a binary merger of two subclusters with comparable masses, a pair of\u0000merger shocks are typically generated, often manifesting as double radio\u0000relics. Using cosmological hydrodynamic simulations, we identify major merger\u0000events with mass ratio $mathcal{M}_1/mathcal{M}_2lesssim4$ and impact\u0000parameter $b/r_{rm vir,1}lesssim1$, where $r_{rm vir,1}$ is the virial\u0000radius of the larger subcluster. We analyze merger shock surfaces approximately\u00001 Gyr after the pericenter passage, focusing on their morphology and the\u0000distribution of the Mach number, $M_s$, of their constituent shock zones. The\u0000shock surfaces exhibit an elongated shape with a minor-to-major axis ratio of\u0000$sim0.6-0.9$ and cover the area of $sim5-20%$ of the enclosed sphere. The\u0000area ratio of the two shock surfaces roughly scales with\u0000$mathcal{M}_1/mathcal{M}_2$, typically positioning the larger shock ahead of\u0000the smaller subcluster. The axis connecting the two subclusters generally does\u0000not pass through the centers of the shock surfaces, due to the nonzero impact\u0000parameter and the turbulent flows around them. The distribution of $M_s$ of\u0000shock zones on each surface can be approximated by a log-normal function,\u0000peaking at $M_{s,rm{peak}}approx2-4.5$ and extending up to $sim10$. The\u0000surface-area-weighted and X-ray-emissivity-weighted average Mach numbers are\u0000comparable, with ${langle{M_s}rangle}_{rm{area}}approx2.3-4.4$ and\u0000${langle{M_s}rangle}_{X}approx2-4$. In contrast, the\u0000cosmic-ray-energy-flux-weighted average Mach numbers are higher with\u0000${langle{M_s}rangle}_{rm{CR}}approx3-5$. This discrepancy aligns with the\u0000differences between Mach numbers derived from X-ray and radio observations of\u0000radio relic shocks. On the other hand, we find that mostly\u0000${langle{M_s}rangle}_{X}gtrsim2$ for simulated merger shocks, although\u0000shocks with $M_{rm X-ray}lesssim2$ are often reported in observations.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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