scholarly journals How to build and use special purpose PC clusters in stellar dynamics

2006 ◽  
Vol 2 (14) ◽  
pp. 426-427
Author(s):  
Rainer Spurzem
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Large Scale ◽  
Stellar Dynamics ◽  
Supermassive Black Holes ◽  
Transport Processes ◽  
Brute Force ◽  
Code Variant

Large scale, direct particle-particle, brute force N-body simulations are required to accurately resolve numerically transport processes of energy and angular momentum due to two-body relaxation, and interactions between supermassive black holes and other particles having a much smaller mass. Direct accurate N-body codes are the widely used tool for such simulations, e.g., NBODY4 or NBODY6 (Aarseth 1999, 2003), see also Harfst et al. (2007) for a less complex code variant, used for benchmarks in this paper. Makino (2002) has presented another direct N-body summation code, which is optimized for a quadratic layout of processor (p required to be a square number).

scholarly journals Gaseous Disks in the Nuclei of Elliptical Galaxies

1997 ◽  
Vol 163 ◽  
pp. 620-625 ◽  
Author(s):  
H. Ford ◽  
Z. Tsvetanov ◽  
L. Ferrarese ◽  
G. Kriss ◽  
W. Jaffe ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Angular Momentum ◽  
Accretion Disks ◽  
Large Scale ◽  
Elliptical Galaxies ◽  
Central Mass ◽  
Massive Black Holes ◽  
Radio Jets

AbstractHST images have led to the discovery that small (r ~ 1″ r ~ 100 – 200 pc), well-defined, gaseous disks are common in the nuclei of elliptical galaxies. Measurements of rotational velocities in the disks provide a means to measure the central mass and search for massive black holes in the parent galaxies. The minor axes of these disks are closely aligned with the directions of the large–scale radio jets, suggesting that it is angular momentum of the disk rather than that of the black hole that determines the direction of the radio jets. Because the disks are directly observable, we can study the disks themselves, and investigate important questions which cannot be directly addressed with observations of the smaller and unresolved central accretion disks. In this paper we summarize what has been learned to date in this rapidly unfolding new field.

scholarly journals The early growth of supermassive black holes in cosmological hydrodynamic simulations with constrained Gaussian realizations

2020 ◽  
Vol 496 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Kuan-Wei Huang ◽  
Yueying Ni ◽  
Yu Feng ◽  
Tiziana Di Matteo
Keyword(s):  
Black Holes ◽  
Large Scale ◽  
Initial Conditions ◽  
Seed Mass ◽  
Early Growth ◽  
Supermassive Black Holes ◽  
Formation Mechanisms ◽  
Density Peak ◽  
Hydrodynamic Simulations ◽  
Small Seed

ABSTRACT The paper examines the early growth of supermassive black holes (SMBHs) in cosmological hydrodynamic simulations with different BH seeding scenarios. Employing the constrained Gaussian realization, we reconstruct the initial conditions in the large-volume bluetides simulation and run them to z = 6 to cross-validate that the method reproduces the first quasars and their environments. Our constrained simulations in a volume of $(15 \, h^{-1} {\rm Mpc})^3$ successfully recover the evolution of large-scale structure and the stellar and BH masses in the vicinity of a ${\sim}10^{12} \, M_{\odot }$ halo which we identified in bluetides at z ∼ 7 hosting a ${\sim}10^9 \, M_{\odot }$ SMBH. Among our constrained simulations, only the ones with a low-tidal field and high-density peak in the initial conditions induce the fastest BH growth required to explain the z > 6 quasars. We run two sets of simulations with different BH seed masses of 5 × 103, 5 × 104, and $5 \times 10^5 \, h^{-1} M_{\odot }$, (i) with the same ratio of halo to BH seed mass and (ii) with the same halo threshold mass. At z = 6, all the SMBHs converge in mass to ${\sim}10^9 \, M_{\odot }$ except for the one with the smallest seed in (ii) undergoing critical BH growth and reaching 108 – $10^9 \, M_{\odot }$, albeit with most of the growth in (ii) delayed compared to set (i). The finding of eight BH mergers in the small-seed scenario (four with masses 104 – $10^6 \, M_{\odot }$ at z > 12), six in the intermediate-seed scenario, and zero in the large-seed scenario suggests that the vast BHs in the small-seed scenario merge frequently during the early phases of the growth of SMBHs. The increased BH merger rate for the low-mass BH seed and halo threshold scenario provides an exciting prospect for discriminating BH formation mechanisms with the advent of multimessenger astrophysics and next-generation gravitational wave facilities.

scholarly journals A FUNDAMENTAL EQUATION FOR SUPERMASSIVE BLACK HOLES

2011 ◽  
Vol 20 (12) ◽  
pp. 2305-2315 ◽  
Author(s):  
ANTONIO FEOLI ◽  
LUIGI MANCINI
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Scaling Laws ◽  
Velocity Dispersion ◽  
Fundamental Equation ◽  
Supermassive Black Holes ◽  
Host Galaxies ◽  
Starting Point ◽  
Interstellar Material ◽  
Energy And Momentum

We developed a theoretical model that is able to give a common origin to the correlations between the mass M• of supermassive black holes and the mass, velocity dispersion, kinetic energy and momentum parameter of the corresponding host galaxies. Our model is essentially based on the transformation of the angular momentum of the interstellar material, which falls into the black hole, into the angular momentum of the radiation emitted in this process. In this framework, we predict the existence of a relation of the form M• ∝ R e σ3, which is confirmed by the experimental data and can be the starting point to understand the other popular scaling laws too.

scholarly journals Changing-look active galactic nuclei: close binaries of supermassive black holes in action

2020 ◽  
Vol 643 ◽  
pp. L9
Author(s):  
Jian-Min Wang ◽  
Edi Bon
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Extreme Case ◽  
Supermassive Black Holes ◽  
Close Binaries ◽  
Orbital Periods

Changing-look active galactic nuclei (CL-AGNs) as a new subpopulation challenge some fundamental physics of AGNs because the timescales of the phenomenon can hardly be reconciled with accretion disk models. In this Letter, we demonstrate the extreme case: close binaries of supermassive black holes (CB-SMBHs) with high eccentricities are able to trigger the CL transition through one orbit. In this scenario, binary black holes build up their own mini-disks by peeling gas off the inner edges of the circumbinary disk during the apastron phase, after which they tidally interact with the disks during the periastron phase to efficiently exchange angular momentum within one orbital period. For mini-disks rotating retrograde to the orbit, the tidal torque rapidly squeezes the tidal parts of the mini-disks into a much smaller radius, which rapidly results in higher accretion and short flares before the disks decline into type-2 AGNs. Prograde-rotation mini-disks gain angular momentum from the binary and rotate outward, which causes a rapid turn-off from type-1 to type-2. Turn-on occurs around the apastron phase. CB-SMBHs control cycle transitions between type-1 and type-2 with orbital periods but allow diverse properties in CL-AGN light curves.

scholarly journals Studying the Evolving Universe with XMM-Newton and Chandra

2003 ◽  
Vol 214 ◽  
pp. 46-58 ◽  
Author(s):  
Günther Hasinger
Keyword(s):  
Black Holes ◽  
High Resolution ◽  
Absorption Line ◽  
Large Scale ◽  
Cosmic Time ◽  
Supermassive Black Holes ◽  
Redshift Distribution ◽  
X Ray ◽  
X Ray Background

Two X-ray observatories, the NASA observatory Chandra and the ESA mission XMM-Newton, provide powerful new diagnostics of the “hot universe”. In this article I review recent X–ray observations of the evolving universe. First indications of the warm/hot intergalactic medium, tracing out the large scale structure of the universe, have been obtained lately in sensitive Chandra and XMM-Newton high resolution absorption line spectroscopy of bright blazars. High resolution X–ray spectroscopy and imaging also provides important new constraints on the physical condition of the cooling matter in the centers of clusters, requiring major modifications to the standard cooling flow models. One possibility is, that the supermassive black hole in the giant central galaxies significantly energizes the gas in the cluster.XMM-Newton and Chandra low resolution spectroscopy detected significant Fe Kα absorption features in the spectrum of the ultraluminous, high redshift lensed broad absorption line QSO APM 08279+5255, yielding new insights in the outflow geometry and in particular indicate a supersolar Fe/O ratio. Chandra high resolution imaging spectroscopy of the nearby ultraluminous infrared galaxy and obscured QSO NGC 6240 for the first time gave evidence of two active supermassive black holes in the same galaxy, likely bound to coalesce in the course of the ongoing major merger in this galaxy.Deep X–ray surveys have shown that the cosmic X-ray background (XRB) is largely due to the accretion onto supermassive black holes, integrated over the cosmic time. These surveys have resolved more than 80 % of the 0.1–10 keV X-ray background into discrete sources. Optical spectroscopic identifications show that the sources producing the bulk of the X-ray background are a mixture of obscured (type–1) and unobscured (type–2) AGNs, as predicted by the XRB population synthesis models. A class of highly luminous type–2 AGN, so called QSO-2s, has been detected in the deepest Chandra and XMM-Newton surveys. The new Chandra AGN redshift distribution peaks at much lower redshifts (z ≈ 0.7) than that based on ROSAT data, indicating that the evolution of Seyfert galaxies occurs at significantly later cosmic time than that of QSOs.

scholarly journals A survey of AGN and supermassive black holes in the COSMOS Survey

2006 ◽  
Vol 2 (S238) ◽  
pp. 287-290 ◽  
Author(s):  
Chris D. Impey ◽  
Jon R. Trump ◽  
Pat J. McCarthy ◽  
Martin Elvis ◽  
John P. Huchra ◽  
...  
Keyword(s):  
Black Holes ◽  
Large Scale ◽  
Supermassive Black Holes ◽  
Host Galaxy ◽  
Data Set ◽  
X Ray ◽  
Cosmic Evolution ◽  
Early Results ◽  
Multi Wavelength ◽  
History Of

AbstractThe Cosmic Evolution Survey (COSMOS) is an HST/ACS imaging survey of 2 square degrees centered on RA = 10:00:28.6, Dec = + 02:12:21 (J2000). While the primary goal of the survey is to study evolution of galaxy morphology and large scale structure, an extensive multi-wavelength data set allows for a sensitive survey of AGN. Spectroscopy of optical counterparts to faint X-ray and radio sources is being carried out with the Magallen (Baade) Telescope and the ESO VLT. By achieving ∼80 redshift completeness down to I AB = 3, the eventual yield of AGN will be ∼1100 over the whole field.Early results on supermassive black holes are described. The goals of the survey include a bolometric census of AGN down to moderate luminosities, the cosmic evolution and fueling history of the central engines, and a study of AGN environments on scales ranging from the host galaxy to clusters and superclusters.

scholarly journals AGN and the Demographics of Supermassive Black Holes

2002 ◽  
Vol 184 ◽  
pp. 335-342
Author(s):  
Richard F. Green
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Large Scale ◽  
Velocity Dispersion ◽  
Cosmic Time ◽  
Volume Density ◽  
Supermassive Black Holes ◽  
High Angular Resolution ◽  
Bulge Formation ◽  
Black Hole Masses

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.

scholarly journals Supermassive Black Holes from Bose-Einstein Condensed Dark Matter—Or Black and Dark Separation by Angular Momentum

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 265
Author(s):  
Masahiro Morikawa
Keyword(s):  
Black Holes ◽  
Dark Matter ◽  
Angular Momentum ◽  
High Redshift ◽  
Difficult Problem ◽  
Supermassive Black Holes ◽  
Dark Halo ◽  
Density Profiles ◽  
Data Scatter ◽  
Bose Einstein

Many supermassive black holes (SMBH) of mass 106∼9M⊙ are observed at the center of each galaxy even in the high redshift (z≈7) Universe. To explain the early formation and the common existence of SMBH, we previously proposed the SMBH formation scenario by the gravitational collapse of the coherent dark matter (DM) composed from the Bose-Einstein Condensed (BEC) objects. A difficult problem in this scenario is the inevitable angular momentum which prevents the collapse of BEC. To overcome this difficulty, in this paper, we consider the very early Universe when the BEC-DM acquires its proper angular momentum by the tidal torque mechanism. The balance of the density evolution and the acquisition of the angular momentum determines the mass of the SMBH as well as the mass ratio of BH and the surrounding dark halo (DH). This ratio is calculated as MBH/MDH≈10−3∼−5(Mtot/1012M⊙)−1/2 assuming simple density profiles of the initial DM cloud. This result turns out to be consistent with the observations at z≈0 and z≈6, although the data scatter is large. Thus, the angular momentum determines the separation of black and dark, i.e., SMBH and DH, in the original DM cloud.

scholarly journals Feeding compact bulges and supermassive black holes with low angular momentum cosmic gas at high redshift

2012 ◽  
Vol 423 (4) ◽  
pp. 3616-3630 ◽  
Author(s):  
Yohan Dubois ◽  
Christophe Pichon ◽  
Martin Haehnelt ◽  
Taysun Kimm ◽  
Adrianne Slyz ◽  
...  
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
High Redshift ◽  
Supermassive Black Holes

scholarly journals Resonant Relaxation

1999 ◽  
Vol 172 ◽  
pp. 391-392
Author(s):  
Scott Tremaine
Keyword(s):  
Black Holes ◽  
Angular Momentum ◽  
Gravitational Field ◽  
Celestial Mechanics ◽  
Protoplanetary Disks ◽  
Stellar Dynamics ◽  
Spherical System ◽  
Massive Black Holes ◽  
Crossing Time ◽  
The Mean

The two main arenas of astrophysical dynamics are celestial mechanics and stellar dynamics. The former deals with the motion of few bodies in a near-Kepler potential; the latter with the motion of many bodies in a non-Kepler potential. I would like to discuss the hybrid problem of many bodies in a near-Kepler potential, which is relevant to a number of astrophysical systems, including protoplanetary disks and the centers of galaxies containing massive black holes.Consider a spherical system of radius r, containing N bodies of mass m orbiting in the gravitational field of a body of mass M ≫ N m. Assume that the orbits have moderate eccentricities and random orientations and imagine taking a time exposure of the system over several orbits. Each body is then smeared into an approximate Kepler ellipse, which precesses slowly on a timescale tprec. Each ellipse exerts a force on other bodies at comparable radius, f ~ Gm/r2. The mean force from all the ellipses is Fm ~ N f. The mean force determines the precession time through the relation L ~ rFmtprec, where L ~ (GMr)1/2 is the specific angular momentum of an orbit. Thus tprec ~ (M/Nm)tcr, where tcr ~ (r3/GM)1/2 is the crossing time.

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