scholarly journals Slow and massive: low-spin SMBHs can grow more

2019 ◽  
Vol 489 (1) ◽  
pp. 1373-1378 ◽  
Author(s):  
Kastytis Zubovas ◽  
Andrew King
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Size Dependence ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Host Galaxies ◽  
The Galaxy ◽  
Mass Increment

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.

scholarly journals Probing the cool ISM in galaxies via 21 cm H i absorption

2012 ◽  
Vol 8 (S292) ◽  
pp. 188-188
Author(s):  
J. R. Allison ◽  
E. M. Sadler ◽  
S. J. Curran ◽  
S. N. Reeves
Keyword(s):  
Spectral Line ◽  
Active Galactic Nuclei ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
The Galaxy ◽  
Early Type Galaxy ◽  
Finding Method ◽  
Compact Array ◽  
Cold Gas

AbstractRecent targeted studies of associated H i absorption in radio galaxies are starting to map out the location, and potential cosmological evolution, of the cold gas in the host galaxies of Active Galactic Nuclei (AGN). The observed 21 cm absorption profiles often show two distinct spectral-line components: narrow, deep lines arising from cold gas in the extended disc of the galaxy, and broad, shallow lines from cold gas close to the AGN (e.g. Morganti et al. 2011). Here, we present results from a targeted search for associated H i absorption in the youngest and most recently-triggered radio AGN in the local universe (Allison et al. 2012b). So far, by using the recently commissioned Australia Telescope Compact Array Broadband Backend (CABB; Wilson et al. 2011), we have detected two new absorbers and one previously-known system. While two of these show both a broad, shallow component and a narrow, deep component (see Fig. 1), one of the new detections has only a single broad, shallow component. Interestingly, the host galaxies of the first two detections are classified as gas-rich spirals, while the latter is an early-type galaxy. These detections were obtained using a spectral-line finding method, based on Bayesian inference, developed for future large-scale absorption surveys (Allison et al. 2012a).

scholarly journals Symmetry and the Arrow of Time in Theoretical Black Hole Astrophysics

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
David Garofalo
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Time Reversal ◽  
Large Scale ◽  
Galactic Nuclei ◽  
Arrow Of Time ◽  
Time Symmetry ◽  
The Universe

While the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. Because astrophysics deals with the largest structures in the Universe, one expects evidence there for the most pronounced entropic arrow of time. However, in recent theoretical astrophysics work it appears possible to identify constructs with time-reversal symmetry, which is puzzling in the large-scale realm especially because it involves the engines of powerful outflows in active galactic nuclei which deal with macroscopic constituents such as accretion disks, magnetic fields, and black holes. Nonetheless, the underlying theoretical structure from which this accreting black hole framework emerges displays a time-symmetric harmonic behavior, a feature reminiscent of basic and simple laws of physics. While we may expect such behavior for classical black holes due to their simplicity, manifestations of such symmetry on the scale of galaxies, instead, surprise. In fact, we identify a parallel between the astrophysical tug-of-war between accretion disks and jets in this model and the time symmetry-breaking of a simple overdamped harmonic oscillator. The validity of these theoretical ideas in combination with this unexpected parallel suggests that black holes are more influential in astrophysics than currently recognized and that black hole astrophysics is a more fundamental discipline.

scholarly journals Recoiling Black Holes: Electromagnetic Signatures, Candidates, and Astrophysical Implications

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
S. Komossa
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Host Galaxies ◽  
Wide Range ◽  
Galaxy Cores ◽  
Galaxy Assembly ◽  
Anisotropic Emission

Supermassive black holes (SMBHs) may not always reside right at the centers of their host galaxies. This is a prediction of numerical relativity simulations, which imply that the newly formed single SMBH, after binary coalescence in a galaxy merger, can receive kick velocities up to several 1000 km/s due to anisotropic emission of gravitational waves. Long-lived oscillations of the SMBHs in galaxy cores, and in rare cases even SMBH ejections from their host galaxies, are the consequence. Observationally, accreting recoiling SMBHs would appear as quasars spatially and/or kinematically offset from their host galaxies. The presence of the “kicks” has a wide range of astrophysical implications which only now are beginning to be explored, including consequences for black hole and galaxy assembly at the epoch of structure formation, black hole feeding, and unified models of active galactic nuclei (AGN). Here, we review the observational signatures of recoiling SMBHs and the properties of the first candidates which have emerged, including follow-up studies of the candidate recoiling SMBH of SDSSJ092712.65+294344.0.

scholarly journals Testing the evolution of correlations between supermassive black holes and their host galaxies using eight strongly lensed quasars

2020 ◽  
Vol 501 (1) ◽  
pp. 269-280
Author(s):  
Xuheng Ding ◽  
Tommaso Treu ◽  
Simon Birrer ◽  
Adriano Agnello ◽  
Dominique Sluse ◽  
...  
Keyword(s):  
Black Holes ◽  
Hubble Space Telescope ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Host Galaxy ◽  
Wide Field ◽  
Host Galaxies ◽  
Field Surveys ◽  
Instrumental Resolution ◽  
The Moment

ABSTRACT One of the main challenges in using high-redshift active galactic nuclei (AGNs) to study the correlations between the mass of a supermassive black hole ($\mathcal {M}_{\rm BH}$) and the properties of its active host galaxy is instrumental resolution. Strong lensing magnification effectively increases instrumental resolution and thus helps to address this challenge. In this work, we study eight strongly lensed AGNs with deep Hubble Space Telescope imaging, using the lens modelling code lenstronomy to reconstruct the image of the source. Using the reconstructed brightness of the host galaxy, we infer the host galaxy stellar mass based on stellar population models. $\mathcal {M}_{\rm BH}$ are estimated from broad emission lines using standard methods. Our results are in good agreement with recent work based on non-lensed AGNs, demonstrating the potential of using strongly lensed AGNs to extend the study of the correlations to higher redshifts. At the moment, the sample size of lensed AGNs is small and thus they provide mostly a consistency check on systematic errors related to resolution for non-lensed AGNs. However, the number of known lensed AGNs is expected to increase dramatically in the next few years, through dedicated searches in ground- and space-based wide-field surveys, and they may become a key diagnostic of black holes and galaxy co-evolution.

scholarly journals Epicyclic Oscillations around Simpson–Visser Regular Black Holes and Wormholes

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 279
Author(s):  
Zdeněk Stuchlík ◽  
Jaroslav Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Observational Data ◽  
High Frequency ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Periodic Oscillations ◽  
High Length ◽  
Circular Geodesic

We study epicyclic oscillatory motion along circular geodesics of the Simpson–Visser meta-geometry describing in a unique way regular black-bounce black holes and reflection-symmetric wormholes by using a length parameter l. We give the frequencies of the orbital and epicyclic motion in a Keplerian disc with inner edge at the innermost circular geodesic located above the black hole outer horizon or on the our side of the wormhole. We use these frequencies in the epicyclic resonance version of the so-called geodesic models of high-frequency quasi-periodic oscillations (HF QPOs) observed in microquasars and around supermassive black holes in active galactic nuclei to test the ability of this meta-geometry to improve the fitting of HF QPOs observational data from the surrounding of supermassive black holes. We demonstrate that this is really possible for wormholes with sufficiently high length parameter l.

An accreting < 105M⊙ black hole at the center of dwarf galaxy IC750

2019 ◽  
Vol 15 (S356) ◽  
pp. 376-376
Author(s):  
Ingyin Zaw
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Host Galaxy ◽  
Scaling Relations ◽  
Host Galaxies ◽  
Seed Formation ◽  
Maser Emission ◽  
Water Masers

AbstractNuclear black holes in dwarf galaxies are important for understanding the low end of the supermassive black hole mass distribution and the black hole-host galaxy scaling relations. IC 750 is a rare system which hosts an AGN, found in ˜0.5% of dwarf galaxies, with circumnuclear 22 GHz water maser emission, found in ˜3–5% of Type 2 AGNs. Water masers, the only known tracer of warm, dense gas in the center parsec of AGNs resolvable in position and velocity, provide the most precise and accurate mass measurements of SMBHs outside the local group. We have mapped the maser emission in IC 750 and find that it traces a nearly edge-on warped disk, 0.2 pc in diameter. The central black hole has an upper limit mass of ˜1 × 105 M⊙ and a best fit mass of ˜8 × 104 M⊙, one to two orders of magnitude below what is expected from black hole-galaxy scaling relations. This has implications for models of black hole seed formation in the early universe, the growth of black holes, and their co-evolution with their host galaxies.

scholarly journals Accretion and Outflow in Active Galaxies

2009 ◽  
Vol 5 (S267) ◽  
pp. 273-282
Author(s):  
Andrew King
Keyword(s):  
Black Hole ◽  
Large Scale ◽  
Host Galaxy ◽  
Small Scale ◽  
Gas Flows ◽  
Inverse Compton ◽  
The Galaxy ◽  
Black Hole Growth ◽  
Lower Excitation ◽  
Hole Growth

AbstractI review accretion and outflow in active galactic nuclei. Accreti4on appears to occur in a series of very small-scale, chaotic events, whose gas flows have no correlation with the large-scale structure of the galaxy or with each other. The accreting gas has extremely low specific angular momentum and probably represents only a small fraction of the gas involved in a galaxy merger, which may be the underlying driver.Eddington accretion episodes in AGN must be common in order for the supermassive black holes to grow. I show that they produce winds with velocities v ~ 0.1c and ionization parameters implying the presence of resonance lines of helium-like and hydrogen-like iron. The wind creates a strong cooling shock as it interacts with the interstellar medium of the host galaxy, and this cooling region may be observable in an inverse Compton continuum and lower-excitation emission lines associated with lower velocities. The shell of matter swept up by the shocked wind stalls unless the black hole mass has reached the value Mσ implied by the M–σ relation. Once this mass is reached, further black hole growth is prevented. If the shocked gas did not cool as asserted above, the resulting (“energy-driven”) outflow would imply a far smaller SMBH mass than actually observed. Minor accretion events with small gas fractions can produce galaxy-wide outflows, including fossil outflows in galaxies where there is little current AGN activity.

scholarly journals Supermassive black holes surrounded by dark matter modeled as anisotropic fluid: epicyclic oscillations and their fitting to observed QPOs

2021 ◽  
Vol 2021 (11) ◽  
pp. 059
Author(s):  
Z. Stuchlík ◽  
J. Vrba
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Dark Matter ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Anisotropic Fluid ◽  
Physical Parameters ◽  
Black Hole Spacetimes ◽  
Test Particles

Abstract Recently introduced exact solution of the Einstein gravity coupled minimally to an anisotropic fluid representing dark matter can well represent supermassive black holes in galactic nuclei with realistic distribution of dark matter around the black hole, given by the Hernquist-like density distribution. For these fluid-hairy black hole spacetimes, properties of the gravitational radiation, quasinormal ringing, and optical phenomena were studied, giving interesting results. Here, using the range of physical parameters of these spacetimes allowing for their relevance in astrophysics, we study the epicyclic oscillatory motion of test particles in these spacetimes. The frequencies of the orbital and epicyclic motion are applied in the epicyclic resonance variant of the geodesic model of quasiperiodic oscillations (QPOs) observed in active galactic nuclei to demonstrate the possibility to solve the cases where the standard vacuum black hole spacetimes are not allowing for explanation of the observed data. We demonstrate that the geodesic model can explain the QPOs observed in most of the active galactic nuclei for the fluid-hairy black holes with reasonable halo parameters.

scholarly journals Numerical Studies of Astrophysical Objects at Fesenkov Astrophysical Institute (FAI)

2018 ◽  
Vol 2 (1) ◽  
pp. 124-134
Author(s):  
Assylkhan Bibossinov ◽  
◽  
Denis Yurin ◽  
Chingis Omarov ◽  
◽  
...  
Keyword(s):  
Black Hole ◽  
Numerical Simulations ◽  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Large Scale ◽  
International Workshop ◽  
Star Clusters ◽  
Galactic Nuclei ◽  
Numerical Studies ◽  
Astrophysical Objects

Numerical studies of astrophysical objects are a relatively new direction in Fesenkov Astrophysical Institute (FAI) and is mainly represented by the Laboratory of Cosmology, Stellar Dynamics and Computational Astrophysics. The lab seeks to understand the evolution of gravitating systems at various scales – from star clusters to galaxies to large-scale structure of the universe as a whole, and tackles these problems both through analytical methods and through numerical simulations. The particular focus is on numerical simulations of star clusters, especially those found in active galactic nuclei – this is a topic of oldestablished collaboration with colleagues from Astronomisches Rechen-Institut (Heidelberg) and National Astronomical Observatories of China (Beijing). The prominent example is STARDISK project dedicated to the numerical research of active galactic nuclei as multicomponent systems composed of compact stellar cluster, gaseous accretion disk and a supermassive black hole. It is demonstrated that an accretion disk can noticeably decelerate stars and thus enhance the accretion rate onto the black hole. In 2013 FAI hosted the MODEST-13 International Workshop dedicated to modeling of star clusters. Recently a new project has been approved aimed at construction of triaxial equilibrium N-body systems that can be of great help in various numerical experiments with disk galaxies. There are also long standing plans to perform cosmological simulations of large scale structures to test a new approach to dark matter and energy actively developed at FAI. For numerical calculations, FAI has a small, but growing computer cluster consisting of several high-performance computing servers equipped with computational GPU cards.

Determination of supermassive black hole spins in active galactic nuclei

2020 ◽  
Vol 35 (02n03) ◽  
pp. 2040054
Author(s):  
M. Yu. Piotrovich ◽  
V. L. Afanasiev ◽  
S. D. Buliga ◽  
T. M. Natsvlishvili
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Disk Model ◽  
Supermassive Black Hole

Based on spectropolarimetry for a number of active galactic nuclei in Seyfert 1 type galaxies observed with the 6-m BTA telescope, we have estimated the spins of the supermassive black holes at the centers of these galaxies. We have determined the spins based on the standard Shakura-Sunyaev accretion disk model. More than 70% of the investigated active galactic nuclei are shown to have Kerr supermassive black holes with a dimensionless spin greater than 0.9.

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