Accretion disc outbursts are re-occurring events observed in various astrophysical systems, including X-ray binaries and cataclysmic variables. These outbursts are characterized by a sudden increase in luminosity due to various instabilities in the accretion disc. We need to investigate the time-dependent accretion flow models to understand the mechanisms driving these outbursts. Time-dependent models incorporate the disc's time evolution and can capture the build-up of instabilities. This review aims to give a basic overview of accretion disc outburst and stability analysis. The paper highlights the necessity of considering the hierarchy of different timescales, dynamical, viscous, and thermal, when investigating the instabilities occurring in the accretion disc. The importance and observational implications of studying these accretion disc outbursts are also discussed.
吸积盘爆发是在各种物理系统（包括 X 射线双星和大灾变变星）中观测到的重复发生的事件。我们需要研究与时间相关的吸积流模型，以了解这些爆发的驱动机制。与时间相关的模型包含了圆盘的时间演化，可以捕捉到不稳定性的积累。本综述旨在介绍吸积盘爆发和稳定性分析的基本概况。本文强调了在研究吸积盘中发生的不稳定性时，考虑不同时间尺度（动力学、粘性和热学）层次的必要性。还讨论了研究这些吸积盘爆发的重要性和观测意义。
{"title":"Accretion Disc Outbursts and Stability Analysis","authors":"Liza Devi, Asish Jyoti Boruah, Biplob Sarkar","doi":"arxiv-2409.11708","DOIUrl":"https://doi.org/arxiv-2409.11708","url":null,"abstract":"Accretion disc outbursts are re-occurring events observed in various\u0000astrophysical systems, including X-ray binaries and cataclysmic variables.\u0000These outbursts are characterized by a sudden increase in luminosity due to\u0000various instabilities in the accretion disc. We need to investigate the\u0000time-dependent accretion flow models to understand the mechanisms driving these\u0000outbursts. Time-dependent models incorporate the disc's time evolution and can\u0000capture the build-up of instabilities. This review aims to give a basic\u0000overview of accretion disc outburst and stability analysis. The paper\u0000highlights the necessity of considering the hierarchy of different timescales,\u0000dynamical, viscous, and thermal, when investigating the instabilities occurring\u0000in the accretion disc. The importance and observational implications of\u0000studying these accretion disc outbursts are also discussed.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260070","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}
In this work, we performed a spectro-temporal investigation of the low-mass X-ray binary GX 9+9 using the Large Area X-ray Proportional Counter (LAXPC) and Soft X- ray Telescope (SXT) observation on board AstroSat. The source was detected in the soft state during the observation, which results in a disk dominating energy spectrum within the energy range of 0.7-25.0 keV. We carried out the analysis at different flux levels. In the temporal analysis, LAXPC data in all flux levels showed the presence of noise components, describing broad Lorentzian components. We modeled the energy-dependent temporal properties of the source in order to identify the radiative origin of the observed variability. This source is not a well-studied source; hence we attempt to estimate various source characteristics like inner-disk radius, flux, and inner-disk temperature.
在这项工作中，我们利用 AstroSat 上的大面积 X 射线比例计数器（LAXPC）和软 X 射线望远镜（SXT）观测，对低质量 X 射线双星 GX 9+9 进行了光谱时间调查。在观测过程中发现该源处于软态，这导致在 0.7-25.0 keV 的能量范围内出现了一个以圆盘为主的能谱。我们在不同的通量水平下进行了分析。在时间分析中，LAXPC 数据在所有通量水平上都显示出噪声成分的存在，描述了宽广的洛伦兹成分。我们模拟了该源随能量变化的时间特性，以确定观测到的可变性的辐射来源。这个源的研究并不深入，因此我们试图估算各种源特征，如内盘半径、通量和内盘温度。
{"title":"Spectro-temporal study of atoll source GX 9+9 observed with AstroSat","authors":"Sree Bhattacherjee, Arbind Pradhan, Biplob Sarkar","doi":"arxiv-2409.11721","DOIUrl":"https://doi.org/arxiv-2409.11721","url":null,"abstract":"In this work, we performed a spectro-temporal investigation of the low-mass\u0000X-ray binary GX 9+9 using the Large Area X-ray Proportional Counter (LAXPC) and\u0000Soft X- ray Telescope (SXT) observation on board AstroSat. The source was\u0000detected in the soft state during the observation, which results in a disk\u0000dominating energy spectrum within the energy range of 0.7-25.0 keV. We carried\u0000out the analysis at different flux levels. In the temporal analysis, LAXPC data\u0000in all flux levels showed the presence of noise components, describing broad\u0000Lorentzian components. We modeled the energy-dependent temporal properties of\u0000the source in order to identify the radiative origin of the observed\u0000variability. This source is not a well-studied source; hence we attempt to\u0000estimate various source characteristics like inner-disk radius, flux, and\u0000inner-disk temperature.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260068","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}
This brief review is based on a lecture given by one of the authors at the international youth conference AYSS-2023. It is devoted to multimessenger astronomy, which studies astrophysical objects and phenomena using various particles and waves that bring information from space. The messengers include electromagnetic and gravitational waves, neutrinos, and cosmic rays. We discuss new opportunities that open up with the combined use of several carriers of information. Combination of data obtained through various observation channels allows one to obtain more complete and accurate information about the processes occurring in the Universe, and even to use it for studying fundamental physics.
{"title":"Multimessenger astronomy","authors":"V. Rozhkov, S. Troitsky","doi":"arxiv-2409.11818","DOIUrl":"https://doi.org/arxiv-2409.11818","url":null,"abstract":"This brief review is based on a lecture given by one of the authors at the\u0000international youth conference AYSS-2023. It is devoted to multimessenger\u0000astronomy, which studies astrophysical objects and phenomena using various\u0000particles and waves that bring information from space. The messengers include\u0000electromagnetic and gravitational waves, neutrinos, and cosmic rays. We discuss\u0000new opportunities that open up with the combined use of several carriers of\u0000information. Combination of data obtained through various observation channels\u0000allows one to obtain more complete and accurate information about the processes\u0000occurring in the Universe, and even to use it for studying fundamental physics.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260067","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}
Nissim Fraija, P. Veres, B. Betancourt Kamenetskaia, A. Galvan-Gamez, M. G. Dainotti, Simone Dichiara, R. L. Becerra
Energetic GeV photons expected from the closest and the most energetic Gamma-ray bursts (GRBs) provide an unique opportunity to study the very-high-energy emission as well as the possible correlations with lower energy bands in realistic GRB afterglow models. In the standard GRB afterglow model, the relativistic homogeneous shock is usually considered to be fully adiabatic, however, it could be partially radiative. Based on the external forward-shock scenario in both stellar wind and constant-density medium. We present a radiative-adiabatic analytical model of the synchrotron self-Compton (SSC) and synchrotron processes considering an electron energy distribution with a power-law index of 1 < p < 2 and 2 $leq$ p. We show that the SSC scenario plays a relevant role in the radiative parameter $epsilon$, leading to a prolonged evolution during the slow cooling regime. In a particular case, we derive the Fermi/LAT light curves together with the photons with energies $geq$ 100 MeV in a sample of nine bursts from the second Fermi/LAT GRB catalog that exhibited temporal and spectral indices with $geq$ 1.5 and $approx$ 2, respectively. These events can hardly be described with closure relations of the standard synchrotron afterglow model, and also exhibit energetic photons above the synchrotron limit. We have modeled the multi-wavelength observations of our sample to constrain the microphysical parameters, the circumburst density, the bulk Lorentz factor and the mechanism responsible for explaining the energetic GeV photons.
预计来自距离最近、能量最高的伽马射线暴（GRB）的高能 GeV 光子为研究现实的 GRB 余辉模型中的极高能发射以及与低能波段的可能相关性提供了一个独特的机会。在标准的 GRB 余辉模型中，相对论均质冲击通常被认为是完全绝热的，然而，它也可能是部分辐射的。基于恒星风和恒密度介质中的外向冲击情景。我们提出了同步辐射自康普顿（SSC）和同步辐射过程的辐射-绝热分析模型，考虑到电子能量分布的幂律指数为1 < p < 2和2 $leq$ p。在一个特殊的案例中，我们推导了费米/LAT光曲线，以及费米/LAT GRB目录第二批中9个爆发样本中能量为100 MeV的光子，它们的时间和光谱指数分别为1.5和2。这些事件很难用标准同步加速器余辉模型的闭合关系来描述，而且还显示出同步加速器极限以上的高能光子。我们对样本的多波长观测进行了建模，以约束微物理参数、环冲密度、体洛伦兹因子以及解释高能 GeV 光子的机制。
{"title":"Synchrotron self-Compton in a radiative-adiabatic fireball scenario: Modelling the multiwavelength observations in some Fermi/LAT bursts","authors":"Nissim Fraija, P. Veres, B. Betancourt Kamenetskaia, A. Galvan-Gamez, M. G. Dainotti, Simone Dichiara, R. L. Becerra","doi":"arxiv-2409.12166","DOIUrl":"https://doi.org/arxiv-2409.12166","url":null,"abstract":"Energetic GeV photons expected from the closest and the most energetic\u0000Gamma-ray bursts (GRBs) provide an unique opportunity to study the\u0000very-high-energy emission as well as the possible correlations with lower\u0000energy bands in realistic GRB afterglow models. In the standard GRB afterglow\u0000model, the relativistic homogeneous shock is usually considered to be fully\u0000adiabatic, however, it could be partially radiative. Based on the external\u0000forward-shock scenario in both stellar wind and constant-density medium. We\u0000present a radiative-adiabatic analytical model of the synchrotron self-Compton\u0000(SSC) and synchrotron processes considering an electron energy distribution\u0000with a power-law index of 1 < p < 2 and 2 $leq$ p. We show that the SSC\u0000scenario plays a relevant role in the radiative parameter $epsilon$, leading\u0000to a prolonged evolution during the slow cooling regime. In a particular case,\u0000we derive the Fermi/LAT light curves together with the photons with energies\u0000$geq$ 100 MeV in a sample of nine bursts from the second Fermi/LAT GRB catalog\u0000that exhibited temporal and spectral indices with $geq$ 1.5 and $approx$ 2,\u0000respectively. These events can hardly be described with closure relations of\u0000the standard synchrotron afterglow model, and also exhibit energetic photons\u0000above the synchrotron limit. We have modeled the multi-wavelength observations\u0000of our sample to constrain the microphysical parameters, the circumburst\u0000density, the bulk Lorentz factor and the mechanism responsible for explaining\u0000the energetic GeV photons.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260064","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}
A. Anitra, C. Miceli, T. Di Salvo, R. Iaria, N. Degenaar, M. Jon Miller, F. Barra, W. Leone, L. Burderi
We propose a novel approach for determining the orbital inclination of low-mass X-ray binary systems by modelling the H$alpha$ and H$beta$ line profiles emitted by the accretion disc, with a Newtonian version of diskline. We applied the model to two sample sources, Swift J1357.2-0933 and MAXI J1305-704, which are both transient black hole systems, and analyse two observations that were collected during a quiescent state and one observation of an outburst. The line profile is well described by the diskline model, although we had to add a Gaussian line to describe the deep inner core of the double-peaked profile, which the diskline model was unable to reproduce. The H$beta$ emission lines in the spectrum of Swift J1357.2-0933 and the H$alpha$ emission lines in that of MAXI J1305-704 during the quiescent state are consistent with a scenario in which these lines originate from a disc ring between $(9.6-57) times 10^{3}, rm{R_{g}}$ and $(1.94-20) times 10^{4}, rm{R_{g}}$, respectively. We estimate an inclination angle of $81 pm 5$ degrees for Swift J1357.2-0933 and an angle of $73 pm 4$ degrees for MAXI J1305-704. This is entirely consistent with the values reported in the literature. In agreement with the recent literature, our analysis of the outburst spectrum of MAXI J1305-704 revealed that the radius of the emission region deviates from expected values. This outcome implies several potential scenarios, including alternative disc configuration or even a circumbinary disc. We caution that these results were derived from a simplistic model that may not fully describe the complicated physics of accretion discs. Despite these limitations, our results for the inclination angles are remarkably consistent with recent complementary studies, and the proposed description of the emitting region remains entirely plausible.
我们将该模型应用于两个样本源：Swift J1357.2-0933和MAXIJ1305-704，它们都是瞬态黑洞系统，并分析了两次静态观测和一次爆发观测。尽管我们不得不添加一条高斯线来描述双峰轮廓的深内核，而盘线模型却无法再现这一轮廓，但盘线模型很好地描述了线轮廓。Swift J1357.2-0933光谱中的H$beta$发射线和MAXI J1305-704静态光谱中的H$alpha$发射线都符合这样一种假设，即这些发射线起源于一个环绕在$(9.6-57) times 10^{3}, rm{R_{g}}$和 $(1.94-20) times 10^{4}, rm{R_{g}}$之间。我们估计 Swift J1357.2-0933 的倾角为 81 （pm 5）度，MAXIJ1305-704 的倾角为 73 （pm 4）度。这与文献报道的数值完全一致。与最近的文献一致，我们对MAXI J1305-704爆发光谱的分析表明，发射区的半径偏离了预期值。这一结果意味着几种可能的情况，包括另一种圆盘构造，甚至是环形圆盘。我们要提醒的是，这些结果是由一个简单的模型得出的，它可能无法完全描述吸积盘的复杂物理现象。尽管存在这些局限性，我们对倾角的研究结果与最近的补充研究结果非常一致，对发射区的描述仍然是完全可信的。
{"title":"X-ray view of emission lines in optical spectra: Spectral analysis of the two low-mass X-ray binary systems Swift J1357.2-0933 and MAXI J1305-704","authors":"A. Anitra, C. Miceli, T. Di Salvo, R. Iaria, N. Degenaar, M. Jon Miller, F. Barra, W. Leone, L. Burderi","doi":"arxiv-2409.11988","DOIUrl":"https://doi.org/arxiv-2409.11988","url":null,"abstract":"We propose a novel approach for determining the orbital inclination of\u0000low-mass X-ray binary systems by modelling the H$alpha$ and H$beta$ line\u0000profiles emitted by the accretion disc, with a Newtonian version of diskline.\u0000We applied the model to two sample sources, Swift J1357.2-0933 and MAXI\u0000J1305-704, which are both transient black hole systems, and analyse two\u0000observations that were collected during a quiescent state and one observation\u0000of an outburst. The line profile is well described by the diskline model,\u0000although we had to add a Gaussian line to describe the deep inner core of the\u0000double-peaked profile, which the diskline model was unable to reproduce. The\u0000H$beta$ emission lines in the spectrum of Swift J1357.2-0933 and the H$alpha$\u0000emission lines in that of MAXI J1305-704 during the quiescent state are\u0000consistent with a scenario in which these lines originate from a disc ring\u0000between $(9.6-57) times 10^{3}, rm{R_{g}}$ and $(1.94-20) times 10^{4},\u0000rm{R_{g}}$, respectively. We estimate an inclination angle of $81 pm 5$\u0000degrees for Swift J1357.2-0933 and an angle of $73 pm 4$ degrees for MAXI\u0000J1305-704. This is entirely consistent with the values reported in the\u0000literature. In agreement with the recent literature, our analysis of the\u0000outburst spectrum of MAXI J1305-704 revealed that the radius of the emission\u0000region deviates from expected values. This outcome implies several potential\u0000scenarios, including alternative disc configuration or even a circumbinary\u0000disc. We caution that these results were derived from a simplistic model that\u0000may not fully describe the complicated physics of accretion discs. Despite\u0000these limitations, our results for the inclination angles are remarkably\u0000consistent with recent complementary studies, and the proposed description of\u0000the emitting region remains entirely plausible.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260065","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}
S. J. Zhao, L. Tao, Q. Q. Yin, S. N. Zhang, R. C. Ma, P. P. Li, Q. C. Zhao, M. Y. Ge, L. Zhang, J. L. Qu, S. Zhang, X. Ma, Y. Huang, J. Q. Peng, Y. X. Xiao
GRS 1716-249 is a stellar-mass black hole in a low-mass X-ray binary that underwent a gaint outburst in 2016/17. In this paper we use simultaneous observations of Insight-HXMT and NuSTAR to determine its basic parameters. The observations were performed during the softest part of the outburst, and the spectra show clear thermal disk emission and reflection features. We have fitted the X-ray energy spectra using the joint fitting method of the continuum and reflection components with the kerrbb2+ relxill model. Since there is a possibility that the distance to this source was previously underestimated, we use the latest distance parameter of 6.9 kpc in our study, in contrast to previous work in which the distance was set at 2.4 kpc. Through spectral fitting of fixing black hole mass at 6.4 $M_{rm odot}$, we observe a strong dependence of the derived spin on the distance: $a_{*}=0.972_{-0.005}^{+0.004}$ at an assumed distance of 2.4 kpc and $a_{*}=0.464_{-0.007}^{+0.016}$ at an assumed distance of 6.9 kpc, at a confidence level of 90%. If considering the uncertainties in the distance and black hole mass, there will be a wider range of spin with $a_{*}$ < 0.78. The fitting results with the new distance indicate that GRS 1716-249 harbors a moderate spin black hole with an inclined ($isim 40-50^{circ}$) accretion disk around it. Additionally, we have also found that solely using the method of the reflection component fitting but ignoring the constraints on the spin from the accretion disk component will result in an extremely high spin.
{"title":"A Revised Spin of the Black Hole in GRS 1716-249 with a New Distance","authors":"S. J. Zhao, L. Tao, Q. Q. Yin, S. N. Zhang, R. C. Ma, P. P. Li, Q. C. Zhao, M. Y. Ge, L. Zhang, J. L. Qu, S. Zhang, X. Ma, Y. Huang, J. Q. Peng, Y. X. Xiao","doi":"arxiv-2409.11927","DOIUrl":"https://doi.org/arxiv-2409.11927","url":null,"abstract":"GRS 1716-249 is a stellar-mass black hole in a low-mass X-ray binary that\u0000underwent a gaint outburst in 2016/17. In this paper we use simultaneous\u0000observations of Insight-HXMT and NuSTAR to determine its basic parameters. The\u0000observations were performed during the softest part of the outburst, and the\u0000spectra show clear thermal disk emission and reflection features. We have\u0000fitted the X-ray energy spectra using the joint fitting method of the continuum\u0000and reflection components with the kerrbb2+ relxill model. Since there is a\u0000possibility that the distance to this source was previously underestimated, we\u0000use the latest distance parameter of 6.9 kpc in our study, in contrast to\u0000previous work in which the distance was set at 2.4 kpc. Through spectral\u0000fitting of fixing black hole mass at 6.4 $M_{rm odot}$, we observe a strong\u0000dependence of the derived spin on the distance: $a_{*}=0.972_{-0.005}^{+0.004}$\u0000at an assumed distance of 2.4 kpc and $a_{*}=0.464_{-0.007}^{+0.016}$ at an\u0000assumed distance of 6.9 kpc, at a confidence level of 90%. If considering the\u0000uncertainties in the distance and black hole mass, there will be a wider range\u0000of spin with $a_{*}$ < 0.78. The fitting results with the new distance indicate\u0000that GRS 1716-249 harbors a moderate spin black hole with an inclined ($isim\u000040-50^{circ}$) accretion disk around it. Additionally, we have also found that\u0000solely using the method of the reflection component fitting but ignoring the\u0000constraints on the spin from the accretion disk component will result in an\u0000extremely high spin.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260066","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}
F. Coti Zelati, D. de Martino, V. S. Dhillon, T. R. Marsh, F. Vincentelli, S. Campana, D. F. Torres, A. Papitto, M. C. Baglio, A. Miraval Zanon, N. Rea, J. Brink, D. A. H. Buckley, P. D'Avanzo, G. Illiano, A. Manca, A. Marino
CXOU J110926.4-650224 is a candidate transitional millisecond pulsar (tMSP) with X-ray and radio emission properties reminiscent of those observed in confirmed tMSPs in their X-ray 'subluminous' disc state. We present the results of observing campaigns that, for the first time, characterise the optical and near-infrared variability of this source and establish a connection with the mode-switching phenomenon observed in X-rays. The optical emission exhibited flickering activity, frequent dipping episodes where it appeared redder, and a multi-peaked flare where it was bluer. The variability pattern was strongly correlated with that of the X-ray emission. Each dip matched an X-ray low-mode episode, indicating that a significant portion of the optical emission originates from nearly the same region as the X-ray emission. The near-infrared emission also displayed remarkable variability, including a dip of 20 min in length during which it nearly vanished. Time-resolved optical spectroscopic observations reveal significant changes in the properties of emission lines from the disc and help infer the spectral type of the companion star to be between K0 and K5. We compare the properties of CXOU J110926.4-650224 with those of other tMSPs in the X-ray subluminous disc state and discuss our findings within the context of a recently proposed scenario that explains the phenomenology exhibited by the prototypical tMSP PSR J1023+0038.
CXOU J110926.4-650224是一颗候选的过渡毫秒脉冲星（tMSP），其X射线和无线电发射特性与在X射线 "亚光 "圆盘状态下观测到的已证实的tMSP的特性相似。我们介绍了观测活动的结果，这些结果首次描述了该星源的光学和近红外变率特征，并与在 X 射线中观测到的模式切换现象建立了联系。光学发射表现出闪烁活动、频繁的倾斜现象（在这种情况下它显得更红）和多峰耀斑（在这种情况下它显得更蓝）。这种变化模式与 X 射线辐射的变化模式密切相关。每次下沉都与 X 射线低模式事件相吻合，这表明光学发射的很大一部分几乎来自 X 射线发射的同一区域。近红外辐射也显示出显著的可变性，包括一次长达 20 分钟的衰减，在此期间，近红外辐射几乎消失。时间分辨光学光谱观测揭示了来自圆盘的发射线性质的显著变化，有助于推断伴星的光谱类型介于 K0 和 K5 之间。我们将CXOU J110926.4-650224的性质与其他处于X射线亚光圆盘状态的tMSP的性质进行了比较，并结合最近提出的一种解释原型tMSP PSR J1023+0038所表现出的现象学的方案来讨论我们的发现。
{"title":"Short-term variability of the transitional pulsar candidate CXOU J110926.4-650224 from X-rays to infrared","authors":"F. Coti Zelati, D. de Martino, V. S. Dhillon, T. R. Marsh, F. Vincentelli, S. Campana, D. F. Torres, A. Papitto, M. C. Baglio, A. Miraval Zanon, N. Rea, J. Brink, D. A. H. Buckley, P. D'Avanzo, G. Illiano, A. Manca, A. Marino","doi":"arxiv-2409.11719","DOIUrl":"https://doi.org/arxiv-2409.11719","url":null,"abstract":"CXOU J110926.4-650224 is a candidate transitional millisecond pulsar (tMSP)\u0000with X-ray and radio emission properties reminiscent of those observed in\u0000confirmed tMSPs in their X-ray 'subluminous' disc state. We present the results\u0000of observing campaigns that, for the first time, characterise the optical and\u0000near-infrared variability of this source and establish a connection with the\u0000mode-switching phenomenon observed in X-rays. The optical emission exhibited\u0000flickering activity, frequent dipping episodes where it appeared redder, and a\u0000multi-peaked flare where it was bluer. The variability pattern was strongly\u0000correlated with that of the X-ray emission. Each dip matched an X-ray low-mode\u0000episode, indicating that a significant portion of the optical emission\u0000originates from nearly the same region as the X-ray emission. The near-infrared\u0000emission also displayed remarkable variability, including a dip of 20 min in\u0000length during which it nearly vanished. Time-resolved optical spectroscopic\u0000observations reveal significant changes in the properties of emission lines\u0000from the disc and help infer the spectral type of the companion star to be\u0000between K0 and K5. We compare the properties of CXOU J110926.4-650224 with\u0000those of other tMSPs in the X-ray subluminous disc state and discuss our\u0000findings within the context of a recently proposed scenario that explains the\u0000phenomenology exhibited by the prototypical tMSP PSR J1023+0038.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260069","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}
Sijia Peng, Ru-Sen Lu, Ciriaco Goddi, Thomas P. Krichbaum, Zhiyuan Li, Ruo-Yu Liu, Jae-Young Kim, Masanori Nakamura, Feng Yuan, Liang Chen, Ivan Marti-Vidal, Zhiqiang Shen
Faraday rotation is an important probe of the magnetic fields and magnetized plasma around active galactic nuclei (AGN) jets. We present a Faraday rotation measure image of the M87 jet between 85.2 GHz and 101.3 GHz with a resolution of ~2" with the Atacama Large Millimeter/submillimeter Array (ALMA). We found that the rotation measure (RM) of the M87 core is $rm (4.5pm 0.4)times10^{4} rad m^{-2}$ with a low linear polarization fraction of $rm (0.88pm 0.08)%$. The spatial RM gradient in the M87 jet spans a wide range from $sim -2times10^4rm~rad m^{-2}$ to $sim 3times10^4rm~rad m^{-2}$ with a typical uncertainty of $0.3times10^4rm~rad m^{-2}$. A comparison with previous RM measurements of the core suggests that the Faraday rotation of the core may originate very close to the super massive black hole (SMBH). Both an internal origin and an external screen with a rapidly varying emitting source could be possible. As for the jet, the RM gradient indicates a helical configuration of the magnetic field that persists up to kpc scale. Combined with the kpc-scale RM measurements at lower frequencies, we found that RM is frequency-dependent in the jet. One possible scenario to explain this dependence is that the kpc-scale jet has a trumpet-like shape and the jet coil unwinds near its end.
{"title":"The Faraday rotation measure of the M87 jet at 3.5mm with the Atacama Large Millimeter/submillimeter Array","authors":"Sijia Peng, Ru-Sen Lu, Ciriaco Goddi, Thomas P. Krichbaum, Zhiyuan Li, Ruo-Yu Liu, Jae-Young Kim, Masanori Nakamura, Feng Yuan, Liang Chen, Ivan Marti-Vidal, Zhiqiang Shen","doi":"arxiv-2409.12028","DOIUrl":"https://doi.org/arxiv-2409.12028","url":null,"abstract":"Faraday rotation is an important probe of the magnetic fields and magnetized\u0000plasma around active galactic nuclei (AGN) jets. We present a Faraday rotation\u0000measure image of the M87 jet between 85.2 GHz and 101.3 GHz with a resolution\u0000of ~2\" with the Atacama Large Millimeter/submillimeter Array (ALMA). We found\u0000that the rotation measure (RM) of the M87 core is $rm (4.5pm\u00000.4)times10^{4} rad m^{-2}$ with a low linear polarization fraction of $rm\u0000(0.88pm 0.08)%$. The spatial RM gradient in the M87 jet spans a wide range\u0000from $sim -2times10^4rm~rad m^{-2}$ to $sim 3times10^4rm~rad m^{-2}$\u0000with a typical uncertainty of $0.3times10^4rm~rad m^{-2}$. A comparison with\u0000previous RM measurements of the core suggests that the Faraday rotation of the\u0000core may originate very close to the super massive black hole (SMBH). Both an\u0000internal origin and an external screen with a rapidly varying emitting source\u0000could be possible. As for the jet, the RM gradient indicates a helical\u0000configuration of the magnetic field that persists up to kpc scale. Combined\u0000with the kpc-scale RM measurements at lower frequencies, we found that RM is\u0000frequency-dependent in the jet. One possible scenario to explain this\u0000dependence is that the kpc-scale jet has a trumpet-like shape and the jet coil\u0000unwinds near its end.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142260098","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}
Hitesh Tanenia, Akash Garg, Ranjeev Misra, Somasri Sen
We present a spectro-timing analysis of the black hole X-ray transient GX 339-4 using simultaneous observations from Astrosat and NICER during the 2021 outburst period. The combined spectrum obtained from NICER, LAXPC, and SXT data is effectively described by a model comprising a thermal disk component, hard Comptonization component, and reflection component with an edge. Our analysis of the Astrosat and NICER spectra indicates the source to be in a low/hard state, with a photon index of ~1.64. The Power Density Spectra (PDS) obtained from both Astrosat and NICER observations exhibit two prominent broad features at 0.22 Hz and 2.94 Hz. We generated energy-dependent time lag and fractional root mean square (frms) at both frequencies in a broad energy range of 0.5-30 keV and found the presence of hard lags along with a decrease in variability at higher energy levels. Additionally, we discovered that the correlated variations in accretion rate, inner disc radius, coronal heating rate, and the scattering fraction, along with a delay between them, can explain the observed frms and lag spectra for both features.
{"title":"Modelling the Energy-dependent broadband variability in the black-hole transient GX 339-4 using Astrosat and NICER","authors":"Hitesh Tanenia, Akash Garg, Ranjeev Misra, Somasri Sen","doi":"arxiv-2409.11875","DOIUrl":"https://doi.org/arxiv-2409.11875","url":null,"abstract":"We present a spectro-timing analysis of the black hole X-ray transient GX\u0000339-4 using simultaneous observations from Astrosat and NICER during the 2021\u0000outburst period. The combined spectrum obtained from NICER, LAXPC, and SXT data\u0000is effectively described by a model comprising a thermal disk component, hard\u0000Comptonization component, and reflection component with an edge. Our analysis\u0000of the Astrosat and NICER spectra indicates the source to be in a low/hard\u0000state, with a photon index of ~1.64. The Power Density Spectra (PDS) obtained\u0000from both Astrosat and NICER observations exhibit two prominent broad features\u0000at 0.22 Hz and 2.94 Hz. We generated energy-dependent time lag and fractional\u0000root mean square (frms) at both frequencies in a broad energy range of 0.5-30\u0000keV and found the presence of hard lags along with a decrease in variability at\u0000higher energy levels. Additionally, we discovered that the correlated\u0000variations in accretion rate, inner disc radius, coronal heating rate, and the\u0000scattering fraction, along with a delay between them, can explain the observed\u0000frms and lag spectra for both features.","PeriodicalId":501343,"journal":{"name":"arXiv - PHYS - High Energy Astrophysical Phenomena","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142269459","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}
Supernova remnants (SNRs) have long been suspected to be the primary sources of Galactic cosmic rays. Over the past decades, great strides have been made in the modelling of particle acceleration, magnetic field amplification, and escape from SNRs. Yet, while many SNRs have been observed in non-thermal emission in radio, X-rays, and gamma-rays, there is no evidence for any individual object contributing to the locally observed flux. Here, we propose a particular spectral signature from individual remnants that is due to the energy-dependent escape from SNRs. For young and nearby sources, we predict fluxes enhanced by tens of percent in narrow rigidity intervals; given the percent-level flux uncertainties of contemporary cosmic-ray data, such features should be readily detectable. We model the spatial and temporal distribution of sources and the resulting distribution of fluxes with a Monte Carlo approach. The decision tree that we have trained on simulated data is able to discriminate with very high significance between the null hypothesis of a smooth distribution of sources and the scenario with a stochastic distribution of individual sources. We suggest that this cosmic-ray energy-dependent injection time (CREDIT) scenario be considered in experimental searches to identify individual SNRs as cosmic-ray sources.
{"title":"Investigating the CREDIT history of supernova remnants as cosmic-ray sources","authors":"Anton Stall, Chun Khai Loo, Philipp Mertsch","doi":"arxiv-2409.11012","DOIUrl":"https://doi.org/arxiv-2409.11012","url":null,"abstract":"Supernova remnants (SNRs) have long been suspected to be the primary sources\u0000of Galactic cosmic rays. Over the past decades, great strides have been made in\u0000the modelling of particle acceleration, magnetic field amplification, and\u0000escape from SNRs. Yet, while many SNRs have been observed in non-thermal\u0000emission in radio, X-rays, and gamma-rays, there is no evidence for any\u0000individual object contributing to the locally observed flux. Here, we propose a\u0000particular spectral signature from individual remnants that is due to the\u0000energy-dependent escape from SNRs. For young and nearby sources, we predict\u0000fluxes enhanced by tens of percent in narrow rigidity intervals; given the\u0000percent-level flux uncertainties of contemporary cosmic-ray data, such features\u0000should be readily detectable. We model the spatial and temporal distribution of\u0000sources and the resulting distribution of fluxes with a Monte Carlo approach.\u0000The decision tree that we have trained on simulated data is able to\u0000discriminate with very high significance between the null hypothesis of a\u0000smooth distribution of sources and the scenario with a stochastic distribution\u0000of individual sources. We suggest that this cosmic-ray energy-dependent\u0000injection time (CREDIT) scenario be considered in experimental searches to\u0000identify individual SNRs as cosmic-ray sources.","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":"142260104","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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