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Luo, Weichen. "The Impact of Super Massive Black Hole (SMBH) on Galaxy and Star". Highlights in Science, Engineering and Technology 38 (16.03.2023): 383–90. http://dx.doi.org/10.54097/hset.v38i.5840.
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Black hole, one of the most inscrutable objects in the universe have been confirmed that nearly every galaxy contain a super massive black hole (SMBH) at its centre. SMBH’s mass is astounding high which contains millions of solar masses, such huge black hole will generate huge gravitational effect on the region nearby. However, studies indeed found the correlation between black hole and its host galaxy. This paper investigates the impact of black holes on galaxies’ structure and stars based on different black hole mass relation simulations. The exact effects on black holes on galaxies remain unclear, but different simulations certainly found the correlations of black hole’s mass with galaxy’s variables and stars. According to the analysis, correlations of MBH, σe, stellar mass, star formation rate and kinetic energy shows the energy emitted by the ANG/black hole affect the inner structure of the galaxy and the properties of stars which disturbing the gas reservoir in the galaxy. The impact on stars can be reflected by the impact on galaxies. Study galaxies is a good way to find more properties and details about the growth and the formation of SMBHs at the centre of the galaxies. The general structure of the galaxy also provides an indication of the structure of the universe and stars’ organizations.
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Voggel, Karina T., Anil C. Seth, Holger Baumgardt, Bernd Husemann, Nadine Neumayer, Michael Hilker, Renuka Pechetti, Steffen Mieske, Antoine Dumont i Iskren Georgiev. "First direct dynamical detection of a dual supermassive black hole system at sub-kiloparsec separation". Astronomy & Astrophysics 658 (luty 2022): A152. http://dx.doi.org/10.1051/0004-6361/202140827.
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We investigated whether the two recently discovered nuclei in NGC 7727 both host a super-massive black hole (SMBH). We used the high spatial resolution mode of the integral-field spectrograph MUSE on the VLT in adaptive optics mode to resolve the stellar kinematics within the sphere of influence of both putative black holes. We combined the kinematic data with an HST-based mass model and used Jeans models to measure their SMBH mass. We report the discovery of a dual SMBH system in NGC 7727. We detect a SMBH in the photometric center of the galaxy in Nucleus 1, with a mass of MSMBH = 1.54−0.15+0.18 × 108 M⊙. In the second nucleus, which is 500 pc offset from the main nucleus, we also find a clear signal for a SMBH with a mass of MBH = 6.33−1.40+3.32 × 106 M⊙. Both SMBHs are detected at high significance. The off-axis nature of Nucleus 2 makes modeling the system challenging; however, a number of robustness tests suggest that a black hole is required to explain the observed kinematics. The SMBH in the offset Nucleus 2 makes up 3.0% of its total mass, which means its SMBH is over-massive compared to the MBH − MBulge scaling relation. This confirms it as the surviving nuclear star cluster of a galaxy that has merged with NGC 7727. This discovery is the first dynamically confirmed dual SMBH system with a projected separation of less than a kiloparsec and the nearest dynamically confirmed dual SMBH at a distance of 27.4 Mpc. The second Nucleus is in an advanced state of inspiral, and it will eventually result in a 1:24 mass ratio SMBH merger. Optical emission lines suggest Nucleus 2 is a Seyfert galaxy, making it a low-luminosity Active Galactic Nuclei. There are likely many more quiescent SMBHs as well as dual SMBH pairs in the local Universe that have been missed by surveys that focus on bright accretion signatures.
3
Hao, Wei, Rainer Spurzem, Thorsten Naab, Long Wang, M. B. N. Kouwenhoven, Pau Amaro-Seoane i Rosemary A. Mardling. "Resonant motions of supermassive black hole triples". Proceedings of the International Astronomical Union 10, S312 (sierpień 2014): 101–4. http://dx.doi.org/10.1017/s1743921315007619.
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AbstractTriple supermassive black holes (SMBH) can form during the hierarchical mergers of massive galaxies with an existing binary. Perturbations by a third black hole may accelerate the merging process of an inner binary, for example through the Kozai mechanism. We analyze the evolution of simulated hierarchical triple SMBHs in galactic centers, and find resonances in the evolution of the semi-major axis, the eccentricity and the inclination, for both the inner and the outer orbits of the triple system, which are not only Kozai like. Through resonant oscillations, SMBH can trigger a significant increase of the inner SMBH binary eccentricity shortening the merger timescale expected from gravitational wave (GW) emission. As hierarchical triple SMBHs may be frequent in massive galaxies, the influence of orbital resonances is of great importance to our understanding of black hole coalescence and gravitational wave detection. Although Kozai mechanism is believed to play an important role in this process, detailed studies on the pattern of these resonances is necessary.
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Ekers, R. D. "Radio evidence for binary super massive black holes". Proceedings of the International Astronomical Union 10, S312 (sierpień 2014): 26–30. http://dx.doi.org/10.1017/s1743921315007401.
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AbstractI present examples of radio AGN with binary nuclei which provide the direct radio evidence for binary Super Massive Black Holes (SMBH) driving the AGN activity. There is also other evidence for distorted radio morphology and periodic variability which may indicate the presence of a second (inactive) SMBH. Finally I enumerate a number of possible radio tracers for the binary SMBH merger events.
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Pognan, Quentin, Benny Trakhtenbrot, Tullia Sbarrato, Kevin Schawinski i Caroline Bertemes. "Searching for super-Eddington quasars using a photon trapping accretion disc model". Monthly Notices of the Royal Astronomical Society 492, nr 3 (13.01.2020): 4058–79. http://dx.doi.org/10.1093/mnras/staa078.
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ABSTRACT Accretion on to black holes at rates above the Eddington limit has long been discussed in the context of supermassive black hole (SMBH) formation and evolution, providing a possible explanation for the presence of massive quasars at high redshifts (z ≳ 7), as well as having implications for SMBH growth at later epochs. However, it is currently unclear whether such ‘super-Eddington’ accretion occurs in SMBHs at all, how common it is, or whether every SMBH may experience it. In this work, we investigate the observational consequences of a simplistic model for super-Eddington accretion flows – an optically thick, geometrically thin accretion disc where the inner-most parts experience severe photon-trapping, which is enhanced with increased accretion rate. The resulting spectral energy distributions (SEDs) show a dramatic lack of rest-frame UV, or even optical, photons. Using a grid of model SEDs spanning a wide range in parameter space (including SMBH mass and accretion rate), we find that large optical quasar surveys (such as SDSS) may be missing most of these luminous systems. We then propose a set of colour selection criteria across optical and infrared colour spaces designed to select super-Eddington SEDs in both wide-field surveys (e.g. using SDSS, 2MASS, and WISE) and deep and narrow-field surveys (e.g. COSMOS). The proposed selection criteria are a necessary first step in establishing the relevance of advection-affected super-Eddington accretion on to SMBHs at early cosmic epochs.
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Yano, Taihei. "Clarification of the formation process of the super massive black hole by Infrared astrometric satellite, Small-JASMINE". Proceedings of the International Astronomical Union 12, S330 (kwiecień 2017): 360–61. http://dx.doi.org/10.1017/s1743921317005476.
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AbstractSmall-JASMINE (hearafter SJ), infrared astrometric satellite, will measure the positions and the proper motions which are located around the Galactic center, by operating at near infrared wave-lengths. SJ will clarify the formation process of the super massive black hole (hearafter SMBH) at the Galactic center. In particular, SJ will determine whether the SMBH was formed by a sequential merging of multiple black holes. The clarification of this formation process of the SMBH will contribute to a better understanding of merging process of satellite galaxies into the Galaxy, which is suggested by the standard galaxy formation scenario. A numerical simulation (Tanikawa and Umemura, 2014) suggests that if the SMBH was formed by the merging process, then the dynamical friction caused by the black holes have influenced the phase space distribution of stars. The phase space distribution measured by SJ will make it possible to determine the occurrences of the merging process.
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Löckmann, Ulf, i Holger Baumgardt. "Tracing Intermediate-Mass Black Holes in the Galactic Centre". Proceedings of the International Astronomical Union 3, S246 (wrzesień 2007): 367–68. http://dx.doi.org/10.1017/s1743921308015974.
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AbstractWe have developed a new method for post-Newtonian, high-precision integration of stellar systems containing a super-massive black hole (SMBH), splitting the forces on a particle between a dominant central force and perturbations. We used this method to perform fully collisional N-body simulations of inspiralling intermediate-mass black holes (IMBHs) in the centre of the Milky Way.
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Dittmann, Alexander J., i M. Coleman Miller. "Star formation in accretion discs and SMBH growth". Monthly Notices of the Royal Astronomical Society 493, nr 3 (17.02.2020): 3732–43. http://dx.doi.org/10.1093/mnras/staa463.
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ABSTRACT Accretion discs around active galactic nuclei (AGNs) are potentially unstable to star formation at large radii. We note that when the compact objects formed from some of these stars spiral into the central supermassive black hole (SMBH), there is no radiative feedback and therefore the accretion rate is not limited by radiation forces. Using a set of accretion disc models, we calculate the accretion rate on to the central SMBH in both gas and compact objects. We find that the time-scale for an SMBH to double in mass can decrease by factors ranging from ∼0.7 to as low as ∼0.1 in extreme cases, compared to gas accretion alone. Our results suggest that the formation of extremely massive black holes at high redshift may occur without prolonged super-Eddington gas accretion or very massive seed black holes. We comment on potential observational signatures as well as implications for other observations of AGNs.
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Wyrzykowski, Łukasz, A. Hamanowicz i K. A. Rybicki. "Tidal Disruption Events and stellar-mass black holes in OGLE and Gaia surveys". Proceedings of the International Astronomical Union 12, S324 (wrzesień 2016): 127–31. http://dx.doi.org/10.1017/s1743921317001636.
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AbstractTidal Disruption Events (TDE) allow to probe the super massive black holes (SMBH) in the cores of galaxies and could be a source of black hole mass growth. We present the search for candidates for TDEs conducted within OGLE and Gaia surveys. Our preliminary results indicate that TDEs can occur in cores of galaxies exhibiting different levels of activity, from quiescent, through weak-AGNs to highly active QSOs. We also present how Gaia can help study the mass distribution of Milky Way single black holes via microlensing.
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Zubovas, Kastytis, i Andrew King. "Slow and massive: low-spin SMBHs can grow more". Monthly Notices of the Royal Astronomical Society 489, nr 1 (12.08.2019): 1373–78. http://dx.doi.org/10.1093/mnras/stz2235.
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Abstract Active galactic nuclei (AGNs) probably control the growth of their host galaxies via feedback in the form of wide-angle wind-driven outflows. These establish the observed correlations between supermassive black hole (SMBH) masses and host galaxy properties, e.g. the spheroid velocity dispersion σ. In this paper we consider the growth of the SMBH once it starts driving a large-scale outflow through the galaxy. To clear the gas and ultimately terminate further growth of both the SMBH and the host galaxy, the black hole must continue to grow its mass significantly, by up to a factor of a few, after reaching this point. The mass increment ΔMBH depends sensitively on both galaxy size and SMBH spin. The galaxy size dependence leads to ΔMBH ∝ σ5 and a steepening of the M–σ relation beyond the analytically calculated M ∝ σ4, in agreement with observation. Slowly spinning black holes are much less efficient in producing feedback, so at any given σ the slowest spinning black holes should be the most massive. Current observational constraints are consistent with this picture, but insufficient to test it properly; however, this should change with upcoming surveys.
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Simon, Joseph. "Exploring Proxies for the Supermassive Black Hole Mass Function: Implications for Pulsar Timing Arrays". Astrophysical Journal Letters 949, nr 2 (30.05.2023): L24. http://dx.doi.org/10.3847/2041-8213/acd18e.
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Abstract Supermassive black holes (SMBHs) reside at the center of every massive galaxy in the local universe with masses that closely correlate with observations of their host galaxy, implying a connected evolutionary history. The population of binary SMBHs, which form following galaxy mergers, is expected to produce a gravitational-wave background (GWB) detectable by pulsar timing arrays (PTAs). PTAs are starting to see hints of what may be a GWB, and the amplitude of the emerging signal is toward the higher end of model predictions. Simulated populations of binary SMBHs can be constructed from observations of galaxies and are used to make predictions about the nature of the GWB. The greatest source of uncertainty in these observation-based models comes from the inference of the SMBH mass function, which is derived from observed host galaxy properties. In this paper, I undertake a new approach for inferring the SMBH mass function, starting from a velocity dispersion function rather than a galaxy stellar mass function. I argue that this method allows for a more direct inference by relying on a larger suite of individual galaxy observations as well as relying on a more “fundamental” SMBH mass relation. I find that the resulting binary SMBH population contains more massive systems at higher redshifts than previous models. Additionally, I explore the implications for the detection of individually resolvable sources in PTA data.
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Giustini, Margherita, i Daniel Proga. "A global view of the inner accretion and ejection flow around super massive black holes". Astronomy & Astrophysics 630 (26.09.2019): A94. http://dx.doi.org/10.1051/0004-6361/201833810.
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Context. Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe. Aims. We aim at providing a simple, coherent, and global view of the sub-parsec accretion and ejection flow in AGN with varying Eddington ratio, ṁ, and black hole mass, MBH. Methods. We made use of theoretical insights, results of numerical simulations, as well as UV and X-ray observations to review the inner regions of AGN by including different accretion and ejection modes, with special emphasis on the role of radiation in driving powerful accretion disk winds from the inner regions around the central SMBH. Results. We propose five ṁ regimes where the physics of the inner accretion and ejection flow around SMBHs is expected to change, and that correspond observationally to quiescent and inactive galaxies; low luminosity AGN (LLAGN); Seyferts and mini-broad absorption line quasars (mini-BAL QSOs); narrow line Seyfert 1 galaxies (NLS1s) and broad absorption line quasars (BAL QSOs); and super-Eddington sources. We include in this scenario radiation-driven disk winds, which are strong in the high ṁ, large MBH regime, and possibly present but likely weak in the moderate ṁ, small MBH regime. Conclusions. A great diversity of the accretion/ejection flows in AGN can be explained to a good degree by varying just two fundamental properties: the Eddington ratio ṁ and the black hole mass MBH, and by the inclusion of accretion disk winds that can naturally be launched by the radiation emitted from luminous accretion disks.
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Green, Richard F. "AGN and the Demographics of Supermassive Black Holes". International Astronomical Union Colloquium 184 (2002): 335–42. http://dx.doi.org/10.1017/s0252921100030980.
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AbstractHigh angular resolution observations from WFPC and STIS now allow well-constrained dynamical measurement of the masses of supermassive black holes (SMBH) in nearby galaxies. An initial statistical analysis by Magorrian et al. showed that 97% of bulges host SMBH. Black hole mass is correlated moderately with bulge luminosity and strongly with the velocity dispersion of the whole bulge, suggesting that black hole formation may be an intrinsic aspect of bulge formation. Black hole masses for AGN determined from reverberation mapping fall on the same relationship with bulge velocity dispersion as those determined from stellar dynamical measurements. The prospect is therefore that the large-scale distribution of black hole masses in distant quasars may be determined through relatively straightforward measurement. Integral constraints show consistency between the total AGN luminosity density and the total volume density in SMBH contained in galaxy bulges. The strong peak of the high-luminosity quasar luminosity function at early cosmic time is consistent with the association of the build-up of SMBH through accretion and bulge formation. Alternate scenarios requiring substantial build-up of the most massive black holes at later cosmic times are more difficult to reconcile with the evolution of the LF.
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Belladitta, S., A. Caccianiga, A. Diana, A. Moretti, P. Severgnini, M. Pedani, L. P. Cassarà i in. "Central engine of the highest redshift blazar". Astronomy & Astrophysics 660 (kwiecień 2022): A74. http://dx.doi.org/10.1051/0004-6361/202142335.
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We present the results of a new LUCI/Large Binocular Telescope near-infrared (NIR) spectroscopic observation of PSO J030947.49+271757.31 (hereafter PSO J0309+27), the highest redshift blazar known to date (z ∼ 6.1). From the CIV λ1549 broad emission line, we found that PSO J0309+27 is powered by a 1.45−0.85+1.89 × 109 M⊙ supermassive black hole (SMBH) with a bolometric luminosity of ∼8 × 1046 erg s−1 and an Eddington ratio equal to 0.44−0.35+0.78. We also obtained new photometric observations with the Telescopio Nazionale Galileo in J and K bands to better constrain the NIR spectral energy distribution of the source. Thanks to these observations, we were able to model the accretion disk and to derive an independent estimate of the black hole mass of PSO J0309+27, confirming the value inferred from the virial technique. The existence of such a massive SMBH just ∼900 million years after the Big Bang challenges models of the earliest SMBH growth, especially if jetted active galactic nuclei are indeed associated with a highly spinning black hole, as is currently assumed. In a Eddington-limited accretion scenario and assuming a radiative efficiency of 0.3, typical of a fast rotating SMBH, a seed black hole of more than 106 M⊙ at z = 30 is indeed required to reproduce the mass of PSO J0309+27 at a redshift of 6. This requirement suggests either earlier periods of rapid black hole growth with super-Eddington accretion or a scenario in which only part of the released gravitational energy goes toward heating the accretion disk and feeding the black hole.
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Bassini, L., E. Rasia, S. Borgani, C. Ragone-Figueroa, V. Biffi, K. Dolag, M. Gaspari i in. "Black hole mass of central galaxies and cluster mass correlation in cosmological hydro-dynamical simulations". Astronomy & Astrophysics 630 (październik 2019): A144. http://dx.doi.org/10.1051/0004-6361/201935383.
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Context. The correlations between the properties of the brightest cluster galaxy (BCG) and the mass of its central super-massive black hole (SMBH) have been extensively studied from a theoretical and observational angle. More recently, relations connecting the SMBH mass and global properties of the hosting cluster, such as temperature and mass, were observed. Aims. We investigate the correlation between SMBH mass and cluster mass and temperature, their establishment and evolution. We compare their scatter to that of the classical MBH − MBCG relation. Moreover, we study how gas accretion and BH-BH mergers contribute to SMBH growth across cosmic time. Methods. We employed 135 groups and clusters with a mass range 1.4 × 1013 M⊙ − 2.5 × 1015 M⊙ extracted from a set of 29 zoom-in cosmological hydro-dynamical simulations where the baryonic physics is treated with various sub-grid models, including feedback by active galactic nuclei. Results. In our simulations we find that MBH correlates well with M500 and T500, with the scatter around these relations compatible within 2σ with the scatter around MBH − MBCG at z = 0. The MBH − M500 relation evolves with time, becoming shallower at lower redshift as a direct consequence of hierarchical structure formation. On average, in our simulations the contribution of gas accretion to the total SMBH mass dominates for the majority of the cosmic time (z > 0.4), while in the last 2 Gyr the BH-BH mergers become a larger contributor. During this last process, substructures hosting SMBHs are disrupted in the merger process with the BCG and the unbound stars enrich the diffuse stellar component rather than increase BCG mass. Conclusions. From the results obtained in our simulations with simple sub-grid models we conclude that the scatter around the MBH − T500 relation is comparable to the scatter around the MBH − MBCG relation and that, given the observational difficulties related to the estimation of the BCG mass, clusters temperature and mass can be a useful proxy for the SMBHs mass, especially at high redshift.
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Arca Sedda, Manuel. "The connection between stellar and nuclear clusters: Can an IMBH be sitting at the heart of the Milky Way?" Proceedings of the International Astronomical Union 14, S351 (maj 2019): 51–55. http://dx.doi.org/10.1017/s1743921319007324.
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AbstractA vast number of observed galactic nuclei are known to harbour a central supermassive black hole (SMBH). In their early lifetime, these systems might have witnessed the strong interaction between the SMBH and massive star clusters formed in the inner galactic regions. Due to the strong tidal field exerted from the SMBH, clusters are likely to undergo tidal disruption, releasing their stars all around the SMBH, and possibly driving the formation of a nuclear cluster (NC). This mechanism can contribute to populate galactic nuclei with intermediate-mass black holes (IMBH). Interactions with the central SMBH can lead to the formation of tight massive BH binaries (MBBH) that undergo coalescence via gravitational waves (GW) emission. We discuss this mechanism in the context of the Milky Way centre, exploring the possibility that SgrA*, the Galactic SMBH, has an IMBH companion.
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Lakhchaura, K., N. Truong i N. Werner. "Correlations between supermassive black holes, hot atmospheres, and the total masses of early-type galaxies". Monthly Notices of the Royal Astronomical Society: Letters 488, nr 1 (16.07.2019): L134—L142. http://dx.doi.org/10.1093/mnrasl/slz114.
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ABSTRACT We present a study of relations between the masses of the central supermassive black holes (SMBHs) and the atmospheric gas temperatures and luminosities measured within a range of radii between Re and 5Re, for a sample of 47 early-type galaxies observed by the Chandra X-ray Observatory. We report the discovery of a tight correlation between the atmospheric temperatures of the brightest cluster/group galaxies (BCGs) and their central SMBH masses. Furthermore, our hydrostatic analysis reveals an approximately linear correlation between the total masses of BCGs (Mtot) and their central SMBH masses (MBH). State-of-the-art cosmological simulations show that the SMBH mass could be determined by the binding energy of the halo through radiative feedback during the rapid black hole growth by accretion, while for the most massive galaxies mergers are the chief channel of growth. In the scenario of a simultaneous growth of central SMBHs and their host galaxies through mergers, the observed linear correlation could be a natural consequence of the central limit theorem.
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Mannerkoski, Matias, Peter H. Johansson, Antti Rantala, Thorsten Naab, Shihong Liao i Alexander Rawlings. "Signatures of the Many Supermassive Black Hole Mergers in a Cosmologically Forming Massive Early-type Galaxy". Astrophysical Journal 929, nr 2 (1.04.2022): 167. http://dx.doi.org/10.3847/1538-4357/ac5f0b.
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Abstract We model here the merger histories of the supermassive black hole (SMBH) population in the late stages of a cosmological simulation of a ∼ 2 × 1013 M ⊙ galaxy group. The gravitational dynamics around the several tens of SMBHs (M • > 7.5 × 107 M ⊙) hosted by the galaxies in the group is computed at high accuracy using regularized integration with the KETJU code. The 11 SMBHs that form binaries and a hierarchical triplet eventually merge after hardening through dynamical friction, stellar scattering, and gravitational wave (GW) emission. The binaries form at eccentricities of e ∼ 0.3–0.9, with one system evolving to a very high eccentricity of e = 0.998, and merge on timescales of a few tens to several hundred megayears. During the simulation, the merger-induced GW recoil kicks eject one SMBH remnant from the central host galaxy. This temporarily drives the galaxy off the M •–σ ⋆ relation; however, the galaxy returns to the relation due to subsequent galaxy mergers, which bring in new SMBHs. This showcases a possible mechanism contributing to the observed scatter of the M •–σ ⋆ relation. Finally, we show that pulsar timing arrays and LISA would be able to detect parts of the GW signals from the SMBH mergers that occur during the ∼4 Gyr time span simulated with KETJU.
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Mannerkoski, Matias, Peter H. Johansson, Antti Rantala, Thorsten Naab, Shihong Liao i Alexander Rawlings. "Signatures of the Many Supermassive Black Hole Mergers in a Cosmologically Forming Massive Early-type Galaxy". Astrophysical Journal 929, nr 2 (1.04.2022): 167. http://dx.doi.org/10.3847/1538-4357/ac5f0b.
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Abstract We model here the merger histories of the supermassive black hole (SMBH) population in the late stages of a cosmological simulation of a ∼ 2 × 1013 M ⊙ galaxy group. The gravitational dynamics around the several tens of SMBHs (M • > 7.5 × 107 M ⊙) hosted by the galaxies in the group is computed at high accuracy using regularized integration with the KETJU code. The 11 SMBHs that form binaries and a hierarchical triplet eventually merge after hardening through dynamical friction, stellar scattering, and gravitational wave (GW) emission. The binaries form at eccentricities of e ∼ 0.3–0.9, with one system evolving to a very high eccentricity of e = 0.998, and merge on timescales of a few tens to several hundred megayears. During the simulation, the merger-induced GW recoil kicks eject one SMBH remnant from the central host galaxy. This temporarily drives the galaxy off the M •–σ ⋆ relation; however, the galaxy returns to the relation due to subsequent galaxy mergers, which bring in new SMBHs. This showcases a possible mechanism contributing to the observed scatter of the M •–σ ⋆ relation. Finally, we show that pulsar timing arrays and LISA would be able to detect parts of the GW signals from the SMBH mergers that occur during the ∼4 Gyr time span simulated with KETJU.
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Haydarov, Kamoliddin, Ahmadjon Abdujabbarov, Javlon Rayimbaev i Bobomurat Ahmedov. "Magnetized Particle Motion around Black Holes in Conformal Gravity: Can Magnetic Interaction Mimic Spin of Black Holes?" Universe 6, nr 3 (17.03.2020): 44. http://dx.doi.org/10.3390/universe6030044.
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Magnetized particle motion around black holes in conformal gravity immersed in asymptotically uniform magnetic field has been studied. We have also analyzed the behavior of magnetic fields near the horizon of the black hole in conformal gravity and shown that with the increase of conformal parameters L and N the value of angular component of magnetic field at the stellar surface decreases. The maximum value of the effective potential corresponding to circular motion of the magnetized particle increases with the increase of conformal parameters. It is shown that in all cases of neutral, charged and magnetized particle collisions in the black hole environment the center-of-mass energy decreases with the increase of conformal parameters L and N. In the case of the magnetized and negatively charged particle collisions, the innermost collision point with the maximum center-of-mass energy comes closer to the central object due to the effects of the parameters of the conformal gravity. We have applied the results to the real astrophysical scenario when a pulsar treated as a magnetized particle is orbiting the super massive black hole (SMBH) Sgr A* in the center of our galaxy in order to obtain the estimation of magnetized compact object’s orbital parameter. The possible detection of pulsar in Sgr A* close environment can provide constraints on black hole parameters. Here we have shown that there is degeneracy between spin of SMBH and ambient magnetic field and consequently the interaction of magnetic field ∼ 10 2 Gauss with magnetic moment of magnetized neutron star can in principle mimic spin of Kerr black holes up to 0.6 .
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Levine, Robyn, Nickolay Y. Gnedin i Andrew J. S. Hamilton. "Growing Supermassive Black Holes Inside Cosmological Simulations". Proceedings of the International Astronomical Union 5, S267 (sierpień 2009): 333. http://dx.doi.org/10.1017/s1743921310006630.
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Using a hydrodynamic adaptive mesh refinement code, we simulate the growth and evolution of a typical disk galaxy hosting a supermassive black hole (SMBH) within a cosmological volume. The simulation covers a dynamical range of 10 million, which allows us to study the transport of matter and angular momentum from super-galactic scales down to the outer edge of the accretion disk around the SMBH. A dynamically interesting circumnuclear disk develops in the central few hundred parsecs of the simulated galaxy, through which gas is stochastically transported to the central black hole.
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Sisk-Reynés, Júlia, Christopher S. Reynolds, James H. Matthews i Robyn N. Smith. "Evidence for a moderate spin from X-ray reflection of the high-mass supermassive black hole in the cluster-hosted quasar H1821+643". Monthly Notices of the Royal Astronomical Society 514, nr 2 (21.06.2022): 2568–80. http://dx.doi.org/10.1093/mnras/stac1389.
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ABSTRACT We present an analysis of deep Chandra Low-Energy and High-Energy Transmission Grating archival observations of the extraordinarily luminous radio-quiet quasar H1821+643, hosted by a rich and massive cool-core cluster at redshift z = 0.3. These data sets provide high-resolution spectra of the AGN at two epochs, free from contamination by the intracluster medium and from the effects of photon pile-up, providing a sensitive probe of the iron-K band. At both epochs, the spectrum is well described by a power-law continuum plus X-ray reflection from both the inner accretion disc and cold, slowly moving distant matter. Adopting this framework, we proceed to examine the properties of the inner disc and the black hole spin. Using Markov chain Monte Carlo (MCMC) methods, we combine constraints from the two epochs assuming that the black hole spin, inner disc inclination, and inner disc iron abundance are invariant. The black hole spin is found to be modest, with a 90 per cent credible range of ${a}^{*}=0.62^{+0.22}_{-0.37}$; and, with a mass MBH in the range log (MBH/M⊙) ∼ 9.2–10.5, this is the most massive black hole candidate for which a well-defined spin constraint has yet been obtained. The modest spin of this black hole supports previous suggestions that the most massive black holes may grow via incoherent or chaotic accretion and/or SMBH-SMBH mergers.
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Forman, W., C. Jones, A. Bogdan, R. Kraft, E. Churazov, S. Randall, M. Sun, E. O’Sullivan, J. Vrtilek i P. Nulsen. "Supermassive Black Hole feedback in early type galaxies". Proceedings of the International Astronomical Union 15, S359 (marzec 2020): 119–25. http://dx.doi.org/10.1017/s1743921320004081.
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AbstractOptically luminous early type galaxies host X-ray luminous, hot atmospheres. These hot atmospheres, which we refer to as coronae, undergo the same cooling and feedback processes as are commonly found in their more massive cousins, the gas rich atmospheres of galaxy groups and galaxy clusters. In particular, the hot coronae around galaxies radiatively cool and show cavities in X-ray images that are filled with relativistic plasma originating from jets powered by supermassive black holes (SMBH) at the galaxy centers. We discuss the SMBH feedback using an X-ray survey of early type galaxies carried out using Chandra X-ray Observatory observations. Early type galaxies with coronae very commonly have weak X-ray active nuclei and have associated radio sources. Based on the enthalpy of observed cavities in the coronae, there is sufficient energy to “balance” the observed radiative cooling. There are a very few remarkable examples of optically faint galaxies that are 1) unusually X-ray luminous, 2) have large dark matter halo masses, and 3) have large SMBHs (e.g., NGC4342 and NGC4291). These properties suggest that, in some galaxies, star formation may have been truncated at early times, breaking the simple scaling relations.
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Frigo, M., T. Naab, A. Rantala, P. H. Johansson, B. Neureiter, J. Thomas i F. Rizzuto. "The two phases of core formation – orbital evolution in the centres of ellipticals with supermassive black hole binaries". Monthly Notices of the Royal Astronomical Society 508, nr 3 (2.10.2021): 4610–24. http://dx.doi.org/10.1093/mnras/stab2754.
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ABSTRACT The flat stellar density cores of massive elliptical galaxies form rapidly due to sinking supermassive black holes (SMBHs) in gas-poor galaxy mergers. After the SMBHs form a bound binary, gravitational slingshot interactions with nearby stars drive the core regions towards a tangentially biased stellar velocity distribution. We use collisionless galaxy merger simulations with accurate collisional orbit integration around the central SMBHs to demonstrate that the removal of stars from the centre by slingshot kicks accounts for the entire change in velocity anisotropy. The rate of strong (unbinding) kicks is constant over several hundred Myr at $\sim 3 \ \mathrm{ M}_\odot\, \rm yr^{-1}$ for our most massive SMBH binary (MBH = 1.7 × 1010 M⊙). Using a frequency-based orbit classification scheme (box, x-tube, z-tube, rosette), we demonstrate that slingshot kicks mostly affect box orbits with small pericentre distances, leading to a velocity anisotropy of β ≲ −0.6 within several hundred Myr as observed in massive ellipticals with large cores. We show how different SMBH masses affect the orbital structure of the merger remnants and present a kinematic tomography connecting orbit families to integral field kinematic features. Our direct orbit classification agrees remarkably well with a modern triaxial Schwarzschild analysis applied to simulated mock kinematic maps.
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Eastwood, Daniel S., Sadegh Khochfar i Arthur Trew. "Mass transport in galaxy discs limits black hole growth to sub-Eddington rates". Monthly Notices of the Royal Astronomical Society 488, nr 2 (17.07.2019): 2006–17. http://dx.doi.org/10.1093/mnras/stz1861.
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ABSTRACT Supermassive black holes (SMBHs) observed to have masses of $M_\bullet \sim 10^9 \, \mathrm{M_\odot }$ at z ≳ 6, <1 Gyr after the big bang, are thought to have been seeded by massive black holes that formed before growing concurrently with the formation of their host galaxies. We model analytically the idealized growth of seed black holes, fed through gas inflow from growing proto-galaxy discs. The inflow depends on the disc gravitational stability and thus varies with black hole and disc mass. We find that for a typical host halo, the efficiency of angular momentum transport, as parametrized by the disc viscosity, is the limiting factor in determining the inflow rate and the black hole accretion rate. For our fiducial case, we find an upper black hole mass estimate of $M_\bullet \sim 1.8 \times 10^7 \, \mathrm{M_{\odot }}$ at z = 6. Only in the extreme case of ∼1016 M⊙ haloes at z = 6 produces SMBH masses of ∼109 M⊙. However, the number density of such haloes is many orders of magnitude below the estimated 1 Gpc−3 of SMBHs at z = 6, indicating that viscosity driven accretion is too inefficient to feed the growth of seeds into $M_\bullet \sim 10^9 \, \mathrm{M_\odot }$ SMBHs by z ∼ 6. We demonstrate that major mergers are capable of resolving the apparent discrepancy in black hole mass at z = 6, with some dependence on the exact choice of orbital parameters of the merger.
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Bustamante, R. Leticia Corral, i Beatriz Eugenia Ochoa Rivera. "Hawking Radiation: Image of the Invisible". Defect and Diffusion Forum 420 (14.11.2022): 26–39. http://dx.doi.org/10.4028/p-f1432s.
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Is it possible to quantify in General Relativity, GR, the entropy generated by Super-Massive Black Holes, SMBH, during its evaporation time, since the intrinsic Hawking radiation in the infinity that, although insignificant, is important in the effects on the thermal quantum atmosphere? The purpose was to develop a formula that allows us to measure the entropy generated during the evaporation time of different types of SMBH of: i. remnant BH of the binary black holes’ merger, BBH: GW150914, GW151226 and LTV151012 detected by the Laser Interferometer Gravitational-Wave Observatory, LIGO, and ii. Schwarzschild, Reissner-Nordström, Kerr and Kerr-Newman, and thus quantify in GR the “insignificant” quantum effects involved, in order to contribute to the validity of the generalized second law, GSL, that directly links the laws of black hole mechanics to the ordinary laws of thermodynamics, as a starting point for unifying quantum effects with GR. This formula could have some relationship with the detection of the shadow’s image of the event horizon of a BH. This formula was developed in dimensional analysis, using the constants of nature and the possible evaporation time of a black hole, to quantify the entropy generated during that time. The energy-stress tensor was calculated with the 4 metrics to obtain the material content and apply the proposed formula. The entropy of the evaporation time of SMBH proved to be insignificant, its temperature is barely above absolute zero, however, the calculation of this type of entropy allows us to argue about the importance of the quantum effects of Hawking radiation mentioned by authors who have studied the quantum effects with arguments that are fundamentally based on the presence of the surrounding thermal atmosphere of the BH.
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Askar, Abbas, Melvyn B. Davies i Ross P. Church. "Formation of supermassive black holes in galactic nuclei – II. Retention and growth of seed intermediate-mass black holes". Monthly Notices of the Royal Astronomical Society 511, nr 2 (9.02.2022): 2631–47. http://dx.doi.org/10.1093/mnras/stab3741.
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ABSTRACT In many galactic nuclei, a nuclear stellar cluster (NSC) co-exists with a supermassive black hole (SMBH). In this second one in a series of papers, we further explore the idea that the NSC forms before the SMBH through the merger of several stellar clusters that may contain intermediate-mass black holes (IMBHs). These IMBHs can subsequently grow by mergers and accretion to form an SMBH. To check the observable consequences of this proposed SMBH seeding mechanism, we created an observationally motivated mock population of galaxies, in which NSCs are constructed by aggregating stellar clusters that may or may not contain IMBHs. Based on several assumptions, we model the growth of IMBHs in the NSCs through gravitational wave (GW) mergers with other IMBHs and gas accretion. In the case of GW mergers, the merged BH can either be retained or ejected depending on the GW recoil kick it receives. The likelihood of retaining the merged BH increases if we consider the growth of IMBHs in the NSC through gas accretion. We find that nucleated lower mass galaxies (${\it M}_{\star } \lesssim 10^{9}\, {\rm M_{\odot }}$; e.g. M33) have an SMBH seed occupation fraction of about 0.3–0.5. This occupation fraction increases with galaxy stellar mass and for more massive galaxies ($\rm 10^{9} \ \lesssim {\it M}_{\star } \lesssim 10^{11}\, {\rm M_{\odot }}$), it is between 0.5 and 0.8, depending on how BH growth is modelled. These occupation fractions are consistent with observational constraints. Furthermore, allowing for BH growth also allows us to reproduce the observed diversity in the mass range of SMBHs in the ${\it M}_{\rm NSC}\!-\!{\it M}_{\rm BH}$ plane.
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Ingram, Adam, Sara E. Motta, Suzanne Aigrain i Aris Karastergiou. "A self-lensing binary massive black hole interpretation of quasi-periodic eruptions". Monthly Notices of the Royal Astronomical Society 503, nr 2 (3.03.2021): 1703–16. http://dx.doi.org/10.1093/mnras/stab609.
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ABSTRACT Binary supermassive black hole (SMBH) systems result from galaxy mergers, and will eventually coalesce due to gravitational wave (GW) emission if the binary separation can be reduced to ≲0.1 pc by other mechanisms. Here, we explore a gravitational self-lensing binary SMBH model for the sharp (duration ∼1 h), quasi-regular X-ray flares – dubbed quasi-periodic eruptions – recently observed from two low-mass active galactic nuclei: GSN 069 and RX J1301.9+2747. In our model, the binary is observed ∼edge-on, such that each SMBH gravitationally lenses light from the accretion disc surrounding the other SMBH twice per orbital period. The model can reproduce the flare spacings if the current eccentricity of RX J1301.9+2747 is ϵ0 ≳ 0.16, implying a merger within ∼1000 yr. However, we cannot reproduce the observed flare profiles with our current calculations. Model flares with the correct amplitude are ∼2/5 the observed duration, and model flares with the correct duration are ∼2/5 the observed amplitude. Our modelling yields three distinct behaviours of self-lensing binary systems that can be searched for in current and future X-ray and optical time-domain surveys: (i) periodic lensing flares, (ii) partial eclipses (caused by occultation of the background mini-disc by the foreground mini-disc), and (iii) partial eclipses with a very sharp in-eclipse lensing flare. Discovery of such features would constitute very strong evidence for the presence of a supermassive binary, and monitoring of the flare spacings will provide a measurement of periastron precession.
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Forman, William, C. Jones i Eugene Churazov. "Chandra and VLA Observations of Supermassive Black Hole Outbursts in M87". Proceedings of the International Astronomical Union 8, S295 (sierpień 2012): 261–64. http://dx.doi.org/10.1017/s1743921313004973.
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AbstractWe discuss the effects of supermassive black hole (SMBH) outbursts on the hot atmospheres surrounding the central massive galaxies in groups and clusters, as observed with X-ray and radio observations. We focus on a detailed study of the supermassive black hole in M87 at the center of the Virgo cluster using Chandra and VLA observations. We summarize the outburst history and describe the clearly observed energy input from buoyant bubbles of relativistic plasma produced by the central SMBH, uplifted filaments of X-ray emitting gas, and the Mach 1.2 shock together balance the energy lost as gas radiatively cools.
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Ritter, Patxi, Sofiane Aoudia, Alessandro D. A. M. Spallicci i Stéphane Cordier. "Indirect (source-free) integration method. I. Wave-forms from geodesic generic orbits of EMRIs". International Journal of Geometric Methods in Modern Physics 13, nr 02 (26.01.2016): 1650021. http://dx.doi.org/10.1142/s0219887816500213.
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The Regge–Wheeler–Zerilli (RWZ) wave-equation describes Schwarzschild–Droste black hole perturbations. The source term contains a Dirac distribution and its derivative. We have previously designed a method of integration in time domain. It consists of a finite difference scheme where analytic expressions, dealing with the wave-function discontinuity through the jump conditions, replace the direct integration of the source and the potential. Herein, we successfully apply the same method to the geodesic generic orbits of EMRI (Extreme Mass Ratio Inspiral) sources, at second order. An EMRI is a Compact Star (CS) captured by a Super-Massive Black Hole (SMBH). These are considered the best probes for testing gravitation in strong regime. The gravitational wave-forms, the radiated energy and angular momentum at infinity are computed and extensively compared with other methods, for different orbits (circular, elliptic, parabolic, including zoom-whirl).
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Fragione, Giacomo, i Fabio Antonini. "Massive binary star mergers in galactic nuclei: implications for blue stragglers, binary S-stars, and gravitational waves". Monthly Notices of the Royal Astronomical Society 488, nr 1 (21.06.2019): 728–38. http://dx.doi.org/10.1093/mnras/stz1723.
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ABSTRACT Galactic nuclei are often found to contain young stellar populations and, in most cases, a central supermassive black hole (SMBH). Most known massive stars are found in binaries or higher multiplicity systems, and in a galactic nucleus the gravitational interaction with the SMBH can affect their long-term evolution. In this paper, we study the orbital evolution of stellar binaries near SMBHs using high precision N-body simulations, and including tidal forces and post-Newtonian corrections to the motion. We focus on the Lidov–Kozai (LK) effect induced by the SMBH on massive star binaries. We investigate how the properties of the merging binaries change with varying the SMBH mass, the slope of the initial mass function, the distributions of the binary orbital parameters, and the efficiency in energy dissipation in dissipative tides. We find that the fraction of merging massive binary stars is in the range ∼4–$15{{\ \rm per\ cent}}$ regardless of the details of the initial distributions of masses and orbital elements. For a Milky Way-like nucleus, we find a typical rate of binary mergers $\Gamma \approx 1.4\times 10^{-7} {\, \rm yr}^{-1}$. The merger products of massive binaries can be rejuvenated blue-straggler stars, more massive than each of their original progenitors, and G2-like objects. Binary systems that survive the LK cycles can be source of X-rays and gravitational waves, observable with present and upcoming instruments.
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Vignali, Cristian. "Obscured accretion from AGN surveys". Proceedings of the International Astronomical Union 9, S304 (październik 2013): 132–38. http://dx.doi.org/10.1017/s1743921314003548.
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AbstractRecent models of super-massive black hole (SMBH) and host galaxy joint evolution predict the presence of a key phase where accretion, traced by obscured Active Galactic Nuclei (AGN) emission, is coupled with powerful star formation. Then feedback processes likely self-regulate the SMBH growth and quench the star-formation activity. AGN in this important evolutionary phase have been revealed in the last decade via surveys at different wavelengths. On the one hand, moderate-to-deep X-ray surveys have allowed a systematic search for heavily obscured AGN, up to very high redshifts (z≈5). On the other hand, infrared/optical surveys have been invaluable in offering complementary methods to select obscured AGN also in cases where the nuclear X-ray emission below 10 keV is largely hidden to our view. In this review I will present my personal perspective of the field of obscured accretion from AGN surveys.
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Umehata, Hideki. "Dusty Starbursts within a z=3 Large Scale Structure revealed by ALMA". Proceedings of the International Astronomical Union 11, S319 (sierpień 2015): 109. http://dx.doi.org/10.1017/s1743921315010327.
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AbstractThe role of the large-scale structure is one of the most important theme in studying galaxy formation and evolution. However, it has been still mystery especially at z>2. On the basis of our ALMA 1.1 mm observations in a z ~ 3 protocluster field, it is suggested that submillimeter galaxies (SMGs) preferentially reside in the densest environment at z ~ 3. Furthermore we find a rich cluster of AGN-host SMGs at the core of the protocluster, combining with Chandra X-ray data. Our results indicate the vigorous star-formation and accelerated super massive black hole (SMBH) growth in the node of the cosmic web.
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Russell, Christopher M. P., Q. Daniel Wang i Jorge Cuadra. "Modelling the thermal X-ray emission around the Galactic centre from colliding Wolf-Rayet winds". Proceedings of the International Astronomical Union 11, S322 (lipiec 2016): 39–42. http://dx.doi.org/10.1017/s1743921316012308.
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AbstractThe Galactic centre is a hotbed of astrophysical activity, with the injection of wind material from ~30 massive Wolf-Rayet (WR) stars orbiting within 12″ of the super-massive black hole (SMBH) playing an important role. Hydrodynamic simulations of such colliding and accreting winds produce a complex density and temperature structure of cold wind material shocking with the ambient medium, creating a large reservoir of hot, X-ray-emitting gas. This work aims to confront the 3Ms of Chandra X-ray Visionary Program (XVP) observations of this diffuse emission by computing the X-ray emission from these hydrodynamic simulations of the colliding WR winds, amid exploring a variety of SMBH feedback mechanisms. The major success of the model is that it reproduces the spectral shape from the 2″–5″ ring around the SMBH, where most of the stellar wind material that is ultimately captured by Sgr A* is shock-heated and thermalised. This naturally explains that the hot gas comes from colliding WR winds, and that the wind speeds of these stars are in general well constrained. The flux level of these spectra, as well as 12″×12″ images of 4–9 keV, show the X-ray flux is tied to the SMBH feedback strength; stronger feedback clears out more hot gas, thereby decreasing the thermal X-ray emission. The model in which Sgr A* produced an intermediate-strength outflow during the last few centuries best matches the observations to within about 10%, showing SMBH feedback is required to interpret the X-ray emission in this region.
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Alister Seguel, P. J., D. R. G. Schleicher, T. C. N. Boekholt, M. Fellhauer i R. S. Klessen. "Formation of SMBH seeds in Population III star clusters through collisions: the importance of mass loss". Monthly Notices of the Royal Astronomical Society 493, nr 2 (17.02.2020): 2352–62. http://dx.doi.org/10.1093/mnras/staa456.
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ABSTRACT Runaway collisions in dense clusters may lead to the formation of supermassive black hole (SMBH) seeds, and this process can be further enhanced by accretion, as recent models of SMBH seed formation in Population III star clusters have shown. This may explain the presence of SMBHs already at high redshift, z > 6. However, in this context, mass loss during collisions was not considered and could play an important role for the formation of the SMBH seed. Here, we study the effect of mass loss, due to collisions of protostars, in the formation and evolution of a massive object in a dense primordial cluster. We consider both constant mass-loss fractions as well as analytic models based on the stellar structure of the collision components. Our calculations indicate that mass loss can significantly affect the final mass of the possible SMBH seed. Considering a constant mass loss of 5 per cent for every collision, we can lose between 60–80 per cent of the total mass that is obtained if mass loss were not considered. Using instead analytical prescriptions for mass loss, the mass of the final object is reduced by 15–40 per cent, depending on the accretion model for the cluster we study. Altogether, we obtain masses of the order of $10^4\, \mathrm{M}_{\odot }$, which are still massive enough to be SMBH seeds.
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Tillman, Megan Taylor, Sarah Wellons, Claude-André Faucher-Giguère, Luke Zoltan Kelley i Daniel Anglés-Alcázar. "Running late: testing delayed supermassive black hole growth models against the quasar luminosity function". Monthly Notices of the Royal Astronomical Society 511, nr 4 (15.02.2022): 5756–67. http://dx.doi.org/10.1093/mnras/stac398.
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ABSTRACT Observations of massive galaxies at low redshift have revealed approximately linear scaling relations between the mass of a supermassive black hole (SMBH) and properties of its host galaxy. How these scaling relations evolve with redshift and whether they extend to lower-mass galaxies, however, remain open questions. Recent galaxy formation simulations predict a delayed, or ‘two-phase,’ growth of SMBHs: slow, highly intermittent BH growth due to repeated gas ejection by stellar feedback in low-mass galaxies, followed by more sustained gas accretion that eventually brings BHs on to the local scaling relations. The predicted two-phase growth implies a steep increase, or ‘kink,’ in BH-galaxy scaling relations at a stellar mass $\rm {M}_{*}\sim 5\times 10^{10}$ M⊙. We develop a parametric, semi-analytic model to compare different SMBH growth models against observations of the quasar luminosity function (QLF) at z ∼ 0.5−4. We compare models in which the relation between SMBH mass and galaxy mass is purely linear versus two-phase models. The models are anchored to the observed galaxy stellar mass function, and the BH mass functions at different redshifts are consistently connected by the accretion rates contributing to the QLF. The best fits suggest that two-phase evolution is significantly preferred by the QLF data over a purely linear scaling relation. Moreover, when the model parameters are left free, the two-phase model fits imply a transition mass consistent with that predicted by simulations. Our analysis motivates further observational tests, including measurements of BH masses and active galactic nuclei activity at the low-mass end, which could more directly test two-phase SMBH growth.
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Spera, Mario, Manuel Arca-Sedda i Roberto Capuzzo-Dolcetta. "The interaction between supermassive black holes and globular clusters". Proceedings of the International Astronomical Union 10, S312 (sierpień 2014): 118–21. http://dx.doi.org/10.1017/s1743921315007656.
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AbstractAlmost all galaxies along the Hubble sequence host a compact massive object (CMO) in their center. The CMO can be either a supermassive black hole (SMBH) or a very dense stellar cluster, also known as nuclear star cluster (NSC). Generally, heavier galaxies (mass ≳ 1011 M⊙) host a central SMBH while lighter show a central NSC. Intermediate mass hosts, instead, contain both a NSC and a SMBH. One possible formation mechanisms of a NSC relies on the dry-merger (migratory) scenario, in which globular clusters (GCs) decay toward the center of the host galaxy and merge. In this framework, the absence of NSCs in high-mass galaxies can be imputed to destruction of the infalling GCs by the intense tidal field of the central SMBH. In this work, we report preliminary results of N-body simulations performed using our high-resolution, direct, code HiGPUs, to investigate the effects of a central SMBH on a single GC orbiting around it. By varying either the mass of the SMBH and the mass of the host galaxy, we derived an upper limit to the mass of the central SMBH, and thus to the mass of the host, above which the formation of a NSC is suppressed.
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Terwel, Jacco H., i Peter G. Jonker. "Discovery of a quasar with double-peaked broad balmer emission lines". Monthly Notices of the Royal Astronomical Society: Letters 512, nr 1 (21.03.2022): L80—L84. http://dx.doi.org/10.1093/mnrasl/slac026.
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ABSTRACT Most massive galaxies contain a supermassive black hole (SMBH) at their centre. When galaxies merge, their SMBHs sink to the centre of the new galaxy, where they are thought to eventually merge. During this process, an SMBH binary is formed. The presence of two sets of broad emission lines in the optical spectrum of an active galactic nucleus (AGN) has been interpreted as evidence for two broad-line regions (BLRs), one surrounding each SMBH in a binary. We modelled the broad Balmer emission lines in the SDSS spectra of 373 extreme variability AGNs using one broad and several narrow Gaussian components. We report on the discovery of SDSS J021647.53 − 011341.5 (hereafter J0216) as a double-peaked broad emission line source. Among the 373 AGNs, there were five sources that are known as double-peaked emission line sources. Three of these have been reported as candidate SMBH binaries in previous studies. We present all six objects and their double-peaked broad Balmer emission lines, and discuss the implications for a tidal disruption event (TDE) interpretation of the extreme variability, assuming the double-peaked sources are SMBH binaries.
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Ramírez-Velásquez, J. M., L. Di G. Sigalotti, R. Gabbasov, J. Klapp i E. Contreras. "Bondi accretion for adiabatic flows onto a massive black hole with an accretion disc". Astronomy & Astrophysics 631 (11.10.2019): A13. http://dx.doi.org/10.1051/0004-6361/201935917.
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We present the classical Bondi accretion theory for the case of non-isothermal accretion processes onto a supermassive black hole (SMBH), including the effects of X-ray heating and the radiation force due to electron scattering and spectral lines. The radiation field is calculated by considering an optically thick, geometrically thin, standard accretion disc as the emitter of UV photons and a spherical central object as a source of X-ray emission. In our analysis, the UV emission from the accretion disc is assumed to have an angular dependence, and the X-ray radiation from the central object is assumed to be isotropic. This allows us to build streamlines in any angular direction. The influence of both types of radiation is evaluated for different flux fractions of the X-ray and UV emissions with and without the effects of spectral line driving. We find that the radiation emitted near the SMBH interacts with the infalling matter and modifies the accretion dynamics. In the presence of line driving, a transition takes place from pure type 1 and 2 to type 5 solutions, which takes place regardless of whether the UV emission dominates the X-ray emission. We computed the radiative factors at which this transition occurs, and discard type 5 solution from all our models. We also provide estimated values of the accretion radius and accretion rate in terms of the classical Bondi values. The results are useful for constructing proper initial conditions for time-dependent hydrodynamical simulations of accretion flows onto SMBHs at the centre of galaxies.
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Biermann, Peter L. "Star and Black Hole Formation at High Redshift". Universe 8, nr 3 (25.02.2022): 146. http://dx.doi.org/10.3390/universe8030146.
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Evidence for dark matter (DM) was originally discovered in 1933 by Zwicky (Zwicky 1933, 1937), and has defied all explanations since then. The original discovery was based on the motions of galaxies in clusters of galaxies. The MicroWave Back Ground (MWBG) observations by the Planck mission and other satellites give definitive numbers. Galaxy correlations give results down to small galaxies, which match theoretical expectations. Here we focus on a few interesting aspects, that may allow to determine the nature of dark matter: (1) Ultra Faint Dwarf (UFD) galaxies, that represent the oldest galaxies known. UFDs are almost devoid of baryonic matter. (2) Calculations show that there can be super-sonic flow of baryonic matter. It follows that there are ubiquitous shockwaves; commonly oblique they generate vorticity. (3) Early virialized clumps, mini-halos, have a density that is consistent with the density implied by Super Massive Black Holes (SMBHs) today, if we assume that SMBHs grow by merging, akin to the Press & Schechter (1974) picture for galaxies. This implies that the oldest SMBHs observed today give powerful constraints on the very early phases.
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Peng, Peng, i Xian Chen. "The last migration trap of compact objects in AGN accretion disc". Monthly Notices of the Royal Astronomical Society 505, nr 1 (17.05.2021): 1324–33. http://dx.doi.org/10.1093/mnras/stab1419.
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ABSTRACT Many black holes detected by the Laser Interferometer Gravitational-wave Observatory (LIGO) and the Virgo detectors are multiple times more massive than those in X-ray binaries. One possibility is that some binary black holes (BBHs) merge within a few Schwarzschild radii of a supermassive black hole (SMBH), so that the gravitational waves (GWs) are highly redshifted, causing the mass inferred from GW signals to appear higher than the real mass. The difficulty of this scenario lies in the delivery of BBH to such a small distance to a SMBH. Here we revisit the theoretical models for the migration of compact objects (COs) in the accretion discs of active galactic nuclei (AGNs). We find that when the accretion rate is high so that the disc is best described by the slim disc model, the COs in the disc could migrate to a radius close to the innermost stable circular orbit and be trapped there for the remaining lifetime of the AGN. The exact trapping radius coincides with the transition region between the sub- and super-Keplerian rotation of the slim disc. We call this region ‘the last migration trap’ because further inward, COs can no longer be trapped for a long time. We pinpoint the parameter space that could induce such a trap and we estimate that the last migration trap contributes a few per cent of the LIGO/Virgo events. Our result implies that a couple of BBHs discovered by LIGO/Virgo so far could have smaller intrinsic masses.
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Nasim, Imran Tariq, Cristobal Petrovich, Adam Nasim, Fani Dosopoulou i Fabio Antonini. "Formation of counter-rotating and highly eccentric massive black hole binaries in galaxy mergers". Monthly Notices of the Royal Astronomical Society 503, nr 1 (9.02.2021): 498–510. http://dx.doi.org/10.1093/mnras/stab351.
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ABSTRACT Supermassive black hole (SMBH) binaries represent the main target for missions such as the Laser Interferometer Space Antenna and Pulsar Timing Arrays. The understanding of their dynamical evolution prior to coalescence is therefore crucial to improving detection strategies and for the astrophysical interpretation of the gravitational wave data. In this paper, we use high-resolution N-body simulations to model the merger of two equal-mass galaxies hosting a central SMBH. In our models, all binaries are initially prograde with respect to the galaxy sense of rotation. But, binaries that form with a high eccentricity, e ≳ 0.7, quickly reverse their sense of rotation and become almost perfectly retrograde at the moment of binary formation. The evolution of these binaries proceeds towards larger eccentricities, as expected for a binary hardening in a counter-rotating stellar distribution. Binaries that form with lower eccentricities remain prograde and at comparatively low eccentricities. We study the origin of the orbital flip by using an analytical model that describes the early stages of binary evolution. This model indicates that the orbital plane flip is due to the torque from the triaxial background mass distribution that naturally arises from the galactic merger process. Our results imply the existence of a population of SMBH binaries with a high eccentricity and could have significant implications for the detection of the gravitational wave signal emitted by these systems.
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Sacchi, Andrea, i Giuseppe Lodato. "The role of stellar rotation in Tidal Disruption Events". Proceedings of the International Astronomical Union 14, S342 (maj 2018): 272–74. http://dx.doi.org/10.1017/s1743921318003691.
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AbstractTidal Disruption Events (TDEs) are highly variable high energy phenomena originating from Galactic Nuclei (Komossa & Bade 1999). TDEs are thus powerful tools to study quiescent Galactic Nuclei given their extreme brightness (several times super-Eddington) and the possibility of being seen in non-AGN galaxies. A TDE is the violent disruption of a star passing by a Super Massive Black Hole (SMBH); after the disruption, roughly half of the star mass gains enough energy to escape from the Black Hole, while the other half is bound to the Hole, falls back and eventually accretes onto it. Early works, (Rees 1988), pointed out a t−5/3 behaviour for the light curves of this event and since then such a time dependency became the signature of these events. Strong deviations are however introduced when one considers the internal stellar structure or if one considers partial disruptions. One feature that has never been taken into account is the effect of stellar rotation in the resulting fallback rate, which is the aim of the present work. Firstly, we will show analytical estimates of the impact of stellar rotation on the TDE and we will then present a set of Smoothed Particle Hydrodynamic simulations of the tidal disruption of rotating stars, performed in order to test these analytical estimates.
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Sassano, Federica, Raffaella Schneider, Rosa Valiante, Kohei Inayoshi, Sunmyon Chon, Kazuyuki Omukai, Lucio Mayer i Pedro R. Capelo. "Light, medium-weight, or heavy? The nature of the first supermassive black hole seeds". Monthly Notices of the Royal Astronomical Society 506, nr 1 (21.06.2021): 613–32. http://dx.doi.org/10.1093/mnras/stab1737.
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ABSTRACT Observations of hyper-luminous quasars at z>6 reveal the rapid growth of supermassive black holes (SMBHs ${\gt}10^9 \,\rm M_{\odot }$) whose origin is still difficult to explain. Their progenitors may have formed as remnants of massive, metal-free stars (light seeds), via stellar collisions (medium-weight seeds) and/or massive gas clouds direct collapse (heavy seeds). In this work, we investigate for the first time the relative role of these three seed populations in the formation of z>6 SMBHs within an Eddington-limited gas accretion scenario. To this aim, we implement in our semi-analytical data-constrained model a statistical description of the spatial fluctuations of Lyman–Werner (LW) photodissociating radiation and of metal/dust enrichment. This allows us to set the physical conditions for black hole seeds formation, exploring their relative birth rate in a highly biased region of the Universe at z>6. We find that the inclusion of medium-weight seeds does not qualitatively change the growth history of the first SMBHs: although less massive seeds (${\lt}10^3\, \rm M_\odot$) form at a higher rate, the mass growth of a ${\sim}10^9\, \rm M_\odot$ SMBH at z<15 is driven by efficient gas accretion (at a sub-Eddington rate) on to its heavy progenitors ($10^5\, \rm M_\odot$). This conclusion holds independently of the critical level of LW radiation and even when medium-weight seeds are allowed to form in higher metallicity galaxies, via the so-called supercompetitive accretion scenario. Our study suggests that the genealogy of z∼6 SMBHs is characterized by a rich variety of BH progenitors, which represent only a small fraction (${\lt} 10{-}20{{\ \rm per\ cent}}$) of all the BHs that seed galaxies at z>15.
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Xu, Yingzhong, Yu Luo, Xi Kang, Zhiyuan Li, Zongnan Li, Peng Wang i Noam Libeskind. "Quenching of Massive Disk Galaxies in the IllustrisTNG Simulation". Astrophysical Journal 928, nr 2 (30.03.2022): 100. http://dx.doi.org/10.3847/1538-4357/ac53ab.
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Abstract A rare population of massive disk galaxies have been found to invade the red sequence dominated by early-type galaxies. The formation and origins of these red/quenched massive disk galaxies have recently gained great interest. The quenching mechanisms that are usually proposed, such as bar quenching and environment quenching, do not seem to be suitable for those bulgeless quenched disks in a low-density environment. In this paper, we use the TNG300 simulation to investigate the formation of massive quenched central disk galaxies. It is found that these galaxies contain less gas than their star-forming counterparts and harbor giant super massive black holes (SMBHs; above 108 M ⊙). By tracing their formation history, we found that quenched disk galaxies formed early and preserved disk morphology for cosmological timescales. They have experienced less than one major merger on average, and mini-mergers (mass ratio <1/10) have mainly contributed to the growth of their SMBHs. In the IllustrisTNG simulation, the black hole feedback mode switches from thermal to kinetic feedback when the black hole mass is more massive than ∼108 M ⊙, which is more efficient to eject gas outside of the galaxy and to suppress further cooling of the hot gaseous halo. We conclude that the dominant quenching mechanism in massive red/quenched disk galaxies is kinetic active galactic nuclei feedback.
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Im, Myungshin. "QSONG: Supermassive Black Holes in Quasars at World's End". Proceedings of the International Astronomical Union 5, S267 (sierpień 2009): 40–45. http://dx.doi.org/10.1017/s1743921310005545.
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AbstractWe present the initial results of the AKARI mission program QSONG (Quasar Spectroscopic Observation with NIR Grism). QSONG utilizes the unique AKARI capability of performing spectroscopic observations at 2.5–5 μm, with the aim of understanding the mass evolution of ~200 quasars at 3.4 < z < 6.5 from their rest-frame optical spectra. The program also studies the rest-frame NIR spectra of 99 well-studied quasars at low redshift (z < 0.5) and 10 red quasars. With the high-redshift QSONG observations, we detect and resolve redshifted optical lines such as Hα for the first time at this redshift, allowing us to measure the supermassive black hole (SMBH) masses at high redshift using the well-calibrated optical mass estimators and provide an independent assessment of UV line-based mass measurements whose reliability has been controversial. Until the launch of JWST, AKARI will be the only facility in the world capable of studying the rest-frame optical spectra of high-redshift objects out to z ~ 6. Our initial QSONG result indicates a lack of very massive SMBHs at z > 5.5, suggesting that we are possibly witnessing the cosmic growth history of the most massive SMBHs (~ 1010M⊙) in the early universe. Ultimately, an extensive study of the rest-frame optical spectra of high-redshift QSOs will help us understand the evolution and the growth of SMBHs in the early universe.
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Casey-Clyde, J. Andrew, Chiara M. F. Mingarelli, Jenny E. Greene, Kris Pardo, Morgan Nañez i Andy D. Goulding. "A Quasar-based Supermassive Black Hole Binary Population Model: Implications for the Gravitational Wave Background". Astrophysical Journal 924, nr 2 (1.01.2022): 93. http://dx.doi.org/10.3847/1538-4357/ac32de.
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Abstract The nanohertz gravitational wave background (GWB) is believed to be dominated by GW emission from supermassive black hole binaries (SMBHBs). Observations of several dual-active galactic nuclei (AGN) strongly suggest a link between AGN and SMBHBs, given that these dual-AGN systems will eventually form bound binary pairs. Here we develop an exploratory SMBHB population model based on empirically constrained quasar populations, allowing us to decompose the GWB amplitude into an underlying distribution of SMBH masses, SMBHB number density, and volume enclosing the GWB. Our approach also allows us to self-consistently predict the number of local SMBHB systems from the GWB amplitude. Interestingly, we find the local number density of SMBHBs implied by the common-process signal in the NANOGrav 12.5-yr data set to be roughly five times larger than previously predicted by other models. We also find that at most ∼25% of SMBHBs can be associated with quasars. Furthermore, our quasar-based approach predicts ≳95% of the GWB signal comes from z ≲ 2.5, and that SMBHBs contributing to the GWB have masses ≳108 M ⊙. We also explore how different empirical galaxy–black hole scaling relations affect the local number density of GW sources, and find that relations predicting more massive black holes decrease the local number density of SMBHBs. Overall, our results point to the important role that a measurement of the GWB will play in directly constraining the cosmic population of SMBHBs, as well as their connections to quasars and galaxy mergers.
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King, Andrew. "GSN 069 – A tidal disruption near miss". Monthly Notices of the Royal Astronomical Society: Letters 493, nr 1 (7.02.2020): L120—L123. http://dx.doi.org/10.1093/mnrasl/slaa020.
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ABSTRACT I suggest that the quasi-periodic ultrasoft X-ray eruptions recently observed from the galaxy GSN 069 may result from accretion from a low-mass white dwarf in a highly eccentric orbit about its central black hole. At $0.21\,\rm M_{\odot }$, this star was probably the core of a captured red giant. Such events should occur in significant numbers as less extreme outcomes of whatever process leads to tidal disruption events. I show that gravitational radiation losses can drive the observed mass-transfer rate, and that the precession of the white dwarf orbit may be detectable in X-rays as a superorbital quasi-period $P_{\rm super} \simeq 2\,{\rm d}$. The very short lifetime of the current event, and the likelihood that similar ones involving more massive stars would be less observable, together suggest that stars may transfer mass to the low-mass SMBH in this and similar galaxies at a total rate, potentially making a significant contribution to their masses. A similar or even much greater inflow rate would be unobservable in most galaxies. I discuss the implications for SMBH mass growth.
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Fragione, Giacomo, Nathan W. C. Leigh i Rosalba Perna. "Black hole and neutron star mergers in galactic nuclei: the role of triples". Monthly Notices of the Royal Astronomical Society 488, nr 2 (1.07.2019): 2825–35. http://dx.doi.org/10.1093/mnras/stz1803.
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ABSTRACT Nuclear star clusters that surround supermassive black holes (SMBHs) in galactic nuclei are thought to contain large numbers of black holes (BHs) and neutron stars (NSs), a fraction of which form binaries and could merge by Kozai–Lidov oscillations (KL). Triple compact objects are likely to be present, given what is known about the multiplicity of massive stars, whose life ends either as an NS or a BH. In this paper, we present a new possible scenario for merging BHs and NSs in galactic nuclei. We study the evolution of a triple black hole (BH) or neutron star (NS) system orbiting an SMBH in a galactic nucleus by means of direct high-precision N-body simulations, including post-Newtonian terms. We find that the four-body dynamical interactions can increase the KL angle window for mergers compared to the binary case and make BH and NS binaries merge on shorter time-scales. We show that the merger fraction can be up to ∼5–8 times higher for triples than for binaries. Therefore, even if the triple fraction is only ∼10–$20\rm{\,per\,cent}$ of the binary fraction, they could contribute to the merger events observed by LIGO/VIRGO in comparable numbers.
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Igarashi, Asuka, Masao Mori i Shin-ya Nitta. "Transonic galactic outflows in a dark matter halo with a central black hole". Proceedings of the International Astronomical Union 11, A29B (sierpień 2015): 741. http://dx.doi.org/10.1017/s1743921316006645.
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AbstractWe study fundamental properties of transonic galactic outflows in the gravitational potential of a cold dark matter halo (DMH) with a central super-massive black hole (SMBH) assuming an isothermal, steady and spherically symmetric state. Transonic solutions of galactic outflows are classified according to their topological features. As result, we find two types of transonic solutions distinguished by a magnitude relationship between the gravity of DMH and that of SMBH. The loci of transonic points for two types are different; one transonic point is formed at a central region (< 0.01kpc) and another is at a very distant region (> 100kpc). Also, mass fluxes and outflow velocities are different for two solutions. Thus, these solutions may differently influence the evolution of galaxies and the release of metals into the intergalactic space.Furthermore, we apply our model to the Sombrero galaxy. In this galaxy, the wide-spread hot gas is detected as the trace of galactic outflows while the star-formation rate is low, and the observed gas density distribution is similar to the hydrostatic state (Li et al. 2011). To solve this discrepancy, we propose a solution that this galaxy has a slowly accelerating outflow; the transonic point forms in a very distant region (~ 120 kpc) and the wide subsonic region spreads across the stellar distribution. Thus, the gas density distribution in the observed region is similar to the hydrostatic state. Such slowly accelerating outflows are different from high-velocity outflows conventionally studied (Igarashi et al. 2014).However, this isothermal model requires an unrealistically large mass flux. Then, we apply the polytropic model to this galaxy incorporating mass flux supplied by stellar components. We find that it can reproduce the observed gas density and the temperature distributions with the realistic mass flux. Thus, our polytropic model successfully demonstrates the existence of the slowly accelerating outflow in the Sombrero galaxy (Igarashi et al. 2015).