Monte Carlo simulations of the evolution of galactic nuclei containing massive, central black holes

1983 ◽  
Vol 268 ◽  
pp. 565 ◽  
Author(s):  
M. J. Duncan ◽  
S. L. Shapiro
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Galactic Nuclei

scholarly journals Monte Carlo Simulations of the 2+1 Dimensional Fokker-Planck Equation: Spherical Star Clusters Containing Massive, Central Black Holes

1985 ◽  
Vol 113 ◽  
pp. 373-413 ◽  
Author(s):  
Stuart L. Shapiro
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Black Hole ◽  
Phase Space ◽  
Star Clusters ◽  
Galactic Nuclei ◽  
Planck Equation ◽  
Time Dependent ◽  
Central Black Hole ◽  
Fokker Planck Equation

The dynamical behavior of a relaxed star cluster containing a massive, central black hole poses a challenging problem for the theorist and intriguing possibilities for the observer. The historical development of the subject is sketched and the salient features of the physical solution and its observational consequences are summarized.The full dynamical problem of a relaxed, self-gravitating, large N-body system containing a massive central black hole has all the necessary ingredients to excite the most dispassionate many-body, computational physicist: it is a time-dependent, multidimensional, nonlinear problem which must be solved over widely disparate length and time scales simultaneously. The problem has been tackled at various levels of approximation over the years. A new 2+1 dimensional Monte Carlo simulation code has been developed in appreciable generality to solve the time-dependent Fokker-Planck equation in E-J space for this problem. The code incorporates such features as (1) a particle “cloning and renormalization” scheme to provide a statistically reliable population of test particles in low density regions of phase space and (2) a time-step “adjustment” algorithm to ensure integration on local relaxation timescales without having to follow typical particles on orbital trajectories. However, critical regions in phase space (e.g. disruption “loss-cone” trajectories) can still be followed on orbital timescales. Numerical results obtained with this Monte Carlo scheme for the dynamical structure and evolution of globular star clusters and dense galactic nuclei containing massive black holes are reviewed.Recent dynamical integrations of the Einstein field equations for spherical, collisionless (Vlasov) systems in General Relativity suggest a possible origin for the supermassive black holes believed to power quasars and active galactic nuclei. This scenario is discussed briefly.

scholarly journals Monte Carlo simulations of black hole mergers in AGN discs: Low χeff mergers and predictions for LIGO

2020 ◽  
Vol 494 (1) ◽  
pp. 1203-1216 ◽  
Author(s):  
B McKernan ◽  
K E S Ford ◽  
R O’Shaugnessy ◽  
D Wysocki
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Black Hole ◽  
Monte Carlo Simulations ◽  
First Generation ◽  
Accretion Discs ◽  
Spin Distribution ◽  
Mass Ratios ◽  
Merger Rate ◽  
Hubble Time

ABSTRACT Accretion discs around supermassive black holes are promising sites for stellar mass black hole mergers detectable with LIGO. Here we present the results of Monte Carlo simulations of black hole mergers within 1-d AGN disc models. For the spin distribution in the disc bulk, key findings are: (1) The distribution of χeff is naturally centred around $\tilde{\chi }_{\rm eff} \approx 0.0$, (2) the width of the χeff distribution is narrow for low natal spins. For the mass distribution in the disc bulk, key findings are: (3) mass ratios $\tilde{q} \sim 0.5\!-\!0.7$, (4) the maximum merger mass in the bulk is $\sim 100\!-\!200\, \mathrm{M}_{\odot }$, (5) $\sim 1{{\ \rm per\ cent}}$ of bulk mergers involve BH $\gt 50\, \mathrm{M}_{\odot }$ with (6) $\simeq 80{{\ \rm per\ cent}}$ of bulk mergers are pairs of first generation BH. Additionally, mergers at a migration trap grow an IMBH with typical merger mass ratios $\tilde{q}\sim 0.1$. Ongoing LIGO non-detections of black holes $\gt 10^{2}\, \mathrm{M}_{\odot }$ puts strong limits on the presence of migration traps in AGN discs (and therefore AGN disc density and structure) as well as median AGN disc lifetime. The highest merger rate occurs for this channel if AGN discs are relatively short-lived (≤1 Myr) so multiple AGN episodes can happen per Galactic nucleus in a Hubble time.

scholarly journals A Markov chain Monte Carlo approach for measurement of jet precession in radio-loud active galactic nuclei

2020 ◽  
Vol 493 (3) ◽  
pp. 3911-3919 ◽  
Author(s):  
Maya A Horton ◽  
Martin J Hardcastle ◽  
Shaun C Read ◽  
Martin G H Krause
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Markov Chain ◽  
Markov Chain Monte Carlo ◽  
Active Galactic Nuclei ◽  
Galaxy Evolution ◽  
Binary Systems ◽  
Galactic Nuclei ◽  
Posterior Probability Distribution ◽  
Cygnus A

ABSTRACT Jet precession can reveal the presence of binary systems of supermassive black holes. The ability to accurately measure the parameters of jet precession from radio-loud active galactic nuclei is important for constraining the binary supermassive black hole population, which is expected as a result of hierarchical galaxy evolution. The age, morphology, and orientation along the line of sight of a given source often result in uncertainties regarding the jet path. This paper presents a new approach for efficient determination of precession parameters using a two-dimensional Markov chain Monte Carlo curve-fitting algorithm that provides us a full posterior probability distribution on the fitted parameters. Applying the method to Cygnus A, we find evidence for previous suggestions that the source is precessing. Interpreting in the context of binary black holes leads to a constraint of parsec scale and likely sub-parsec orbital separation for the putative supermassive binary.

scholarly journals A Statistical Method for Detecting Gravitational Recoils of Supermassive Black Holes in Active Galactic Nuclei

2016 ◽  
Vol 12 (S324) ◽  
pp. 227-230
Author(s):  
P. Raffai ◽  
B. Bécsy ◽  
Z. Haiman ◽  
Z. Frei
Keyword(s):  
Black Holes ◽  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Line Of Sight ◽  
Galactic Centre ◽  
Type Ii ◽  
Host Galaxies

AbstractWe propose an observational test for gravitationally recoiling supermassive black holes in active galactic nuclei, based on a positive correlation between the velocities of black holes relative to their host galaxies, |Δv|, and their obscuring dust column densities, Σdust, both measured along the line of sight. Our findings using a set of toy models implemented to a Monte Carlo simulation imply that models of the galactic centre and of recoil dynamics can be tested by future observations of the potential Σdust–|Δv| correlation. We have also found that the fraction of obscured quasars decreases with |Δv|, for which the predicted trend can be compared to the observed fraction of type II quasars, and can further test combinations of models we may implement.

scholarly journals Monte Carlo simulations of dusty gas discs around supermassive black holes

2006 ◽  
Vol 2 (S238) ◽  
pp. 321-322
Author(s):  
Maarten Baes ◽  
Sławomir Piasecki
Keyword(s):  
Black Holes ◽  
Monte Carlo ◽  
Black Hole ◽  
Interstellar Dust ◽  
Galactic Nuclei ◽  
Dusty Gas ◽  
Black Hole Mass ◽  
Mass Measurements ◽  
Rotation Curves ◽  
Black Hole Masses

AbstractUsing detailed Monte Carlo radiative transfer simulations in realistic models for galactic nuclei, we critically investigate the influence of interstellar dust in ionised gas discs on the rotation curves and the resulting black hole mass measurements. We find that absorption and scattering by interstellar dust leaves the shape of the rotation curves basically unaltered, but slightly decreases the central slope of the rotation curves. As a result, the “observed” black hole masses are systematically underestimated by some 10 to 20% for realistic optical depths.

Low-voltage EDS of magnesium ferrite Dendrites in a FEG-SEM

1996 ◽  
Vol 54 ◽  
pp. 478-479
Author(s):  
Matthew T. Johnson ◽  
Ian M. Anderson ◽  
Jim Bentley ◽  
C. Barry Carter
Keyword(s):  
Monte Carlo ◽  
Quantitative Analysis ◽  
Monte Carlo Simulations ◽  
Cross Section ◽  
Spatial Resolution ◽  
Low Voltage ◽  
Magnesium Ferrite ◽  
X Ray ◽  
Interaction Volume ◽  
Ferrite Spinel

Energy-dispersive X-ray spectrometry (EDS) performed at low (≤ 5 kV) accelerating voltages in the SEM has the potential for providing quantitative microanalytical information with a spatial resolution of ∼100 nm. In the present work, EDS analyses were performed on magnesium ferrite spinel [(MgxFe1−x)Fe2O4] dendrites embedded in a MgO matrix, as shown in Fig. 1. spatial resolution of X-ray microanalysis at conventional accelerating voltages is insufficient for the quantitative analysis of these dendrites, which have widths of the order of a few hundred nanometers, without deconvolution of contributions from the MgO matrix. However, Monte Carlo simulations indicate that the interaction volume for MgFe2O4 is ∼150 nm at 3 kV accelerating voltage and therefore sufficient to analyze the dendrites without matrix contributions.Single-crystal {001}-oriented MgO was reacted with hematite (Fe2O3) powder for 6 h at 1450°C in air and furnace cooled. The specimen was then cleaved to expose a clean cross-section suitable for microanalysis.

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