N-body simulations of globular clusters in tidal fields: Effects of intermediate-mass black holes

Lutzgendorf, N., Baumgardt, H. and Kruijssen, J. M. D. (2013) N-body simulations of globular clusters in tidal fields: Effects of intermediate-mass black holes. Astronomy and Astrophysics, 558 . doi:10.1051/0004-6361/201321927

Author Lutzgendorf, N.
Baumgardt, H.
Kruijssen, J. M. D.
Title N-body simulations of globular clusters in tidal fields: Effects of intermediate-mass black holes
Journal name Astronomy and Astrophysics   Check publisher's open access policy
ISSN 0004-6361
Publication date 2013-01-01
Year available 2013
Sub-type Article (original research)
DOI 10.1051/0004-6361/201321927
Open Access Status DOI
Volume 558
Total pages 10
Place of publication Les Ulis, France
Publisher E D P Sciences
Language eng
Subject 3103 Astronomy and Astrophysics
1912 Space and Planetary Science
Abstract Context. Intermediate-mass black holes (IMBHs) may provide the missing link to understanding the growth of supermassive black holes in the early Universe. Some formation scenarios predict that IMBHs could have formed by runaway collisions in globular clusters (GCs). However, it is challenging to set observational constraints on the mass of a black hole in a largely gas-free (and hence accretion-free) stellar system such as a GC. Understanding the influence of an IMBH in the center of a GC on its environment might provide indirect detection methods. Aims. Our goal is to test the effects of different initial compositions of GCs on their evolution in a tidal field. We pin down the crucial observables that indicate the presence of an IMBH at the center of the cluster. In addition to central IMBHs, we also consider the effects of different stellar-mass black hole retention and stellar binary fractions. Methods. We performed a set of 22 N-body simulations and varied particle numbers, IMBH masses, stellar-mass black-hole retention fractions, and stellar binary fractions. These models are all run in an external tidal field to study the effect of black holes on the cluster mass loss, mass function, and life times. Finally, we compared our results with observational data. Results. We found that a central massive black hole increases the escape rate of high-mass stars from a star cluster, implying that the relative depletion of the mass function at the low-mass end proceeds less rapidly. Furthermore, we found a similar behavior for a cluster hosting a high number of stellar-mass black holes instead of one massive central IMBH. The presence of an IMBH also weakly affects the fraction of the cluster mass that is constituted by stellar remnants, as does the presence of primordial binaries. We compared our simulations with observational data from the literature and found good agreement between our models and observed mass functions and structural parameters of GCs. We exploited this agreement to identify GCs that could potentially host IMBHs.
Keyword Black hole physics
Galaxies: star clusters: general
Methods: numerical
Stars: kinematics and dynamics
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
Official 2014 Collection
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