Supermassive black holes with billion solar masses are in place already within the first Gyr, however, their origin and growth in such a short lapse of time is extremely challenging to understand. Here, we discuss the formation paths of early black-hole seeds, showing the limits of light black-hole seeds from stellar origin and the expected characteristics of heavy/massive black-hole seeds originated by gas direct collapse in peculiar primordial conditions. To draw conclusions on the possible candidates and the role of the ambient medium, we use results from N-body hydrodynamic simulations including atomic and molecular non-equilibrium abundance calculations, cooling, star formation, feedback mechanisms, stellar evolution, metal spreading of several heavy elements from SNII, AGB and SNIa, and multifrequency radiative transfer over 150 frequencies coupled to chemistry and SED emission for popII-I and popIII stellar sources. Standard stellar-origin light black holes are unlikely to be reliable seeds of early supermassive black holes, because, under realistic assumptions, they cannot grow significantly in less than a billion years. Alternatively, massive black-hole seeds might originate from direct collapse of pristine gas in primordial quiescent mini-haloes that are exposed to stellar radiation from nearby star forming regions. The necessary conditions required to form these heavy seeds must be complemented with information on the complex features of local environments and the fine balance between chemistry evolution and radiative transfer.
在第一Gyr中已经有了数十亿太阳质量的超大质量黑洞，然而，它们在如此短的时间内的起源和增长是极具挑战性的。在这里，我们讨论了早期黑洞种子的形成路径，显示了来自恒星起源的轻黑洞种子的局限性以及在特殊原始条件下由气体直接坍缩产生的重/大质量黑洞种子的预期特征。为了得出可能的候选物质和环境介质的作用，我们使用了n体流体动力学模拟的结果，包括原子和分子非平衡丰度计算、冷却、恒星形成、反馈机制、恒星演化、SNII、AGB和SNIa中几种重元素的金属扩散，以及popi - i - i和popIII恒星源的150多个频率的多频辐射传输，以及化学和SED发射。标准恒星起源的光黑洞不太可能是早期超大质量黑洞的可靠种子，因为在现实的假设下，它们不可能在不到10亿年的时间里显著增长。另一种说法是，大质量黑洞的种子可能起源于原始静止微晕中原始气体的直接坍缩，这些微晕暴露在附近恒星形成区域的恒星辐射中。形成这些重种子所需的必要条件必须辅以有关当地环境的复杂特征和化学演化与辐射转移之间的微妙平衡的信息。
{"title":"Early black-hole seeds in the first billion years","authors":"U. Maio","doi":"10.22323/1.362.0014","DOIUrl":"https://doi.org/10.22323/1.362.0014","url":null,"abstract":"Supermassive black holes with billion solar masses are in place already within the first Gyr, however, their origin and growth in such a short lapse of time is extremely challenging to understand. Here, we discuss the formation paths of early black-hole seeds, showing the limits of light black-hole seeds from stellar origin and the expected characteristics of heavy/massive black-hole seeds originated by gas direct collapse in peculiar primordial conditions. To draw conclusions on the possible candidates and the role of the ambient medium, we use results from N-body hydrodynamic simulations including atomic and molecular non-equilibrium abundance calculations, cooling, star formation, feedback mechanisms, stellar evolution, metal spreading of several heavy elements from SNII, AGB and SNIa, and multifrequency radiative transfer over 150 frequencies coupled to chemistry and SED emission for popII-I and popIII stellar sources. Standard stellar-origin light black holes are unlikely to be reliable seeds of early supermassive black holes, because, under realistic assumptions, they cannot grow significantly in less than a billion years. Alternatively, massive black-hole seeds might originate from direct collapse of pristine gas in primordial quiescent mini-haloes that are exposed to stellar radiation from nearby star forming regions. The necessary conditions required to form these heavy seeds must be complemented with information on the complex features of local environments and the fine balance between chemistry evolution and radiative transfer.","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124927972","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 review, I have tried to focus on the development of the field, from the first speculations to the current lines of research. According to Einstein's theory of general relativity, black holes are relatively simple objects and completely characterized by their mass, spin angular momentum, and electric charge, but the latter can be ignored in the case of astrophysical macroscopic objects. Search for black holes in the sky started in the early 1970s with the dynamical measurement of the mass of the compact object in Cygnus X-1. In the past 10-15 years, astronomers have developed some techniques for measuring the black hole spins. Recently, we have started using astrophysical black holes for testing fundamental physics.
{"title":"Astrophysical Black Holes: A Review","authors":"C. Bambi","doi":"10.22323/1.362.0028","DOIUrl":"https://doi.org/10.22323/1.362.0028","url":null,"abstract":"In this review, I have tried to focus on the development of the field, from the first speculations to the current lines of research. According to Einstein's theory of general relativity, black holes are relatively simple objects and completely characterized by their mass, spin angular momentum, and electric charge, but the latter can be ignored in the case of astrophysical macroscopic objects. Search for black holes in the sky started in the early 1970s with the dynamical measurement of the mass of the compact object in Cygnus X-1. In the past 10-15 years, astronomers have developed some techniques for measuring the black hole spins. Recently, we have started using astrophysical black holes for testing fundamental physics.","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123167831","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}
N. Shakura, D. Kolesnikov, K. Postnov, I. Volkov, I. Bikmaev, T. Irsmambetova, R. Staubert, J. Wilms, E. Irtuganov, P. Shurygin, P. Golysheva, S. Shugarov, I. Nikolenko, E. Trunkovsky, G. Schonherr, A. Schwope, D. Klochkov
In this work are presented the results of modelling of 35 d superorbital changes of B and V lightcurves and X-ray flux of HZ Her/Her X-1. The model implemented in the new code written in C programming language, with module for parameter optimisation written in Python. The model includes a tilted precessing and warped accretion disc around a freely precessing neutron star. The disc is warped near its inner edge due to interaction with the rotating neutron star magnetosphere. The magnetic torque depends on the precessional phase of the neutron star. The X-ray emission flux from the neutron star also depends on the free precession phase which modulates the X-ray illumination of the optical star atmosphere and the intensity of gas streams. We demonstrate that this model is able to well reproduce both optical observations of HZ Her and the behaviour of the 35-day X-ray cycle.
{"title":"Multi-frequency long-term observations of Her X-1 - The 35-d cycle","authors":"N. Shakura, D. Kolesnikov, K. Postnov, I. Volkov, I. Bikmaev, T. Irsmambetova, R. Staubert, J. Wilms, E. Irtuganov, P. Shurygin, P. Golysheva, S. Shugarov, I. Nikolenko, E. Trunkovsky, G. Schonherr, A. Schwope, D. Klochkov","doi":"10.22323/1.362.0047","DOIUrl":"https://doi.org/10.22323/1.362.0047","url":null,"abstract":"In this work are presented the results of modelling of 35 d superorbital changes of B and V lightcurves and X-ray flux of HZ Her/Her X-1. The model implemented in the new code written in C programming language, with module for parameter optimisation written in Python. The model includes a tilted precessing and warped accretion disc around a freely precessing neutron star. The disc is warped near its inner edge due to interaction with the rotating neutron star magnetosphere. The magnetic torque depends on the precessional phase of the neutron star. The X-ray emission flux from the neutron star also depends on the free precession phase which modulates the X-ray illumination of the optical star atmosphere and the intensity of gas streams. We demonstrate that this model is able to well reproduce both optical observations of HZ Her and the behaviour of the 35-day X-ray cycle.","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123537063","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}
J. Beall, K. Lind, P. Meintjes, D. Rose, M. Wolff, Brian vanSoelen, Izak vanderWesthuizen
We present results of fully three-dimensional (3-D) simulations of astrophysical jets. These ef- forts use the the PLUTO code (Mignone et al. 2007) run in a highly parallel environment for the hydrodynamic, magneto-hydrodynamic (MHD), relativistic hydrodynamic (RHD), and relativis- tic, magnetohydrodynamic (RMHD) simulations. In this work, we focus on RMHD simulations, but also present estimations of the 15 GHz radio flux based on RHD simulations post-processed to show the radio-emission from the astrophysical jets. Keywords: jets, active galaxies, blazars, intracluster medium, non-linear dynamics, plasma as- trophysics, computational fluid dynamics, relativistic, magnetized fluid flows.
我们提出了天体物理喷流的全三维(3-D)模拟结果。这些努力使用PLUTO代码(Mignone et al. 2007)在一个高度并行的环境中运行，用于流体动力学、磁流体动力学(MHD)、相对论流体动力学(RHD)和相对论磁流体动力学(RMHD)模拟。在这项工作中，我们专注于RMHD模拟，但也提出了基于RHD模拟后处理的15ghz无线电通量估计，以显示天体物理射流的无线电发射。关键词:喷流，活动星系，耀发星，星系团内介质，非线性动力学，等离子体物理，计算流体动力学，相对论，磁化流体流动。
{"title":"Large-Scale Hydrodynamic Simulations of Astrophysical Jets","authors":"J. Beall, K. Lind, P. Meintjes, D. Rose, M. Wolff, Brian vanSoelen, Izak vanderWesthuizen","doi":"10.22323/1.331.0060","DOIUrl":"https://doi.org/10.22323/1.331.0060","url":null,"abstract":"We present results of fully three-dimensional (3-D) simulations of astrophysical jets. These ef- \u0000forts use the the PLUTO code (Mignone et al. 2007) run in a highly parallel environment for the \u0000hydrodynamic, magneto-hydrodynamic (MHD), relativistic hydrodynamic (RHD), and relativis- \u0000tic, magnetohydrodynamic (RMHD) simulations. In this work, we focus on RMHD simulations, \u0000but also present estimations of the 15 GHz radio flux based on RHD simulations post-processed \u0000to show the radio-emission from the astrophysical jets. \u0000Keywords: jets, active galaxies, blazars, intracluster medium, non-linear dynamics, plasma as- \u0000trophysics, computational fluid dynamics, relativistic, magnetized fluid flows.","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130862977","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}
I present the publicly available code GLADIS (GLobal Accretion Disk Instability Simulation) developed in my reserach group over the years 2002-2017. It can be freely downloaded and modified by the users via the link from the Astrophysics Source Code Library. The software computes time-dependent evolution of a black hole accretion disk, in one-dimensional, axisymmetric, vertically integrated scheme. The main applications are to explain the variability of accretion disks that can be subject to radiation-pressure instability. The phenomenon is relevant for fast variable microquasars, as well as for a class of changing-look AGN.
{"title":"GLADIS: GLobal Accretion Disk Instability Simulation","authors":"A. Janiuk","doi":"10.22323/1.362.0048","DOIUrl":"https://doi.org/10.22323/1.362.0048","url":null,"abstract":"I present the publicly available code GLADIS (GLobal Accretion Disk Instability Simulation) developed in my reserach group over the years 2002-2017. \u0000It can be freely downloaded and modified by the users via the link from the Astrophysics Source Code Library. The software computes time-dependent evolution of a black hole accretion disk, in one-dimensional, axisymmetric, vertically integrated scheme. The main applications are to explain the variability of accretion disks that can be subject to radiation-pressure instability. The phenomenon is relevant for fast variable microquasars, as well as for a class of changing-look AGN.","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130172545","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}
Pub Date : 2016-12-03DOI: 10.1007/978-3-319-44729-2
R. Poggiani
{"title":"High Energy Astrophysical Techniques","authors":"R. Poggiani","doi":"10.1007/978-3-319-44729-2","DOIUrl":"https://doi.org/10.1007/978-3-319-44729-2","url":null,"abstract":"","PeriodicalId":265862,"journal":{"name":"Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2016-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116844418","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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