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Binary black hole mergers from globular clusters : The impact of globular cluster properties

Hong, Jongsuk ; Vesperini, Enrico ; Askar, Abbas LU orcid ; Giersz, Mirek ; Szkudlarek, Magdalena and Bulik, Tomasz (2018) In Monthly Notices of the Royal Astronomical Society 480(4). p.5645-5656
Abstract

The dense environment of globular clusters (GCs) can facilitate the formation of binary black holes (BBHs), some of which can merge with gravitational waves within the age of the Universe. We have performed a survey of Monte Carlo simulations following the dynamical evolution of GCs with different masses, sizes, and binary fractions and explored the impact of the host GC properties on the formation of BBH mergers. We find that the number of BBH mergers from GCs is determined by the GC's initial mass, size, and primordial binary fraction. We identify two groups of BBH mergers: a primordial group whose formation does not depend on cluster's dynamics, and a dynamical group whose formation is driven by the cluster's dynamical evolution. We... (More)

The dense environment of globular clusters (GCs) can facilitate the formation of binary black holes (BBHs), some of which can merge with gravitational waves within the age of the Universe. We have performed a survey of Monte Carlo simulations following the dynamical evolution of GCs with different masses, sizes, and binary fractions and explored the impact of the host GC properties on the formation of BBH mergers. We find that the number of BBH mergers from GCs is determined by the GC's initial mass, size, and primordial binary fraction. We identify two groups of BBH mergers: a primordial group whose formation does not depend on cluster's dynamics, and a dynamical group whose formation is driven by the cluster's dynamical evolution. We show how the BBH origin affects the BBH mergers' main properties such as the chirp mass and merging time distributions. We provide analytic expressions for the dependence of the number of BBH mergers from individual GCs on the main cluster's structural properties and the time evolution of the merger rates of these BBHs. These expressions provide an essential ingredient for a general framework allowing to estimate the merger rate density. Using the relations found in our study, we find a local merger rate density of 0.18-1.8 Gpc-3 yr-1 for primordial BBH mergers and 0.6-18 Gpc-3 yr-1 for dynamical BBH mergers, depending on the GC mass and size distributions, initial binary fraction, and the number density of GCs in the Universe.

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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Globular clusters: general, Gravitational waves, Stars: black holes
in
Monthly Notices of the Royal Astronomical Society
volume
480
issue
4
pages
12 pages
publisher
Oxford University Press
external identifiers
  • scopus:85054738760
ISSN
0035-8711
DOI
10.1093/mnras/sty2211
language
English
LU publication?
yes
id
1e7390d3-36f4-4aad-8a7c-840a2ff758b1
date added to LUP
2018-11-13 11:59:01
date last changed
2021-10-06 02:40:41
@article{1e7390d3-36f4-4aad-8a7c-840a2ff758b1,
  abstract     = {<p>The dense environment of globular clusters (GCs) can facilitate the formation of binary black holes (BBHs), some of which can merge with gravitational waves within the age of the Universe. We have performed a survey of Monte Carlo simulations following the dynamical evolution of GCs with different masses, sizes, and binary fractions and explored the impact of the host GC properties on the formation of BBH mergers. We find that the number of BBH mergers from GCs is determined by the GC's initial mass, size, and primordial binary fraction. We identify two groups of BBH mergers: a primordial group whose formation does not depend on cluster's dynamics, and a dynamical group whose formation is driven by the cluster's dynamical evolution. We show how the BBH origin affects the BBH mergers' main properties such as the chirp mass and merging time distributions. We provide analytic expressions for the dependence of the number of BBH mergers from individual GCs on the main cluster's structural properties and the time evolution of the merger rates of these BBHs. These expressions provide an essential ingredient for a general framework allowing to estimate the merger rate density. Using the relations found in our study, we find a local merger rate density of 0.18-1.8 Gpc<sup>-3</sup> yr<sup>-1</sup> for primordial BBH mergers and 0.6-18 Gpc<sup>-3</sup> yr<sup>-1</sup> for dynamical BBH mergers, depending on the GC mass and size distributions, initial binary fraction, and the number density of GCs in the Universe.</p>},
  author       = {Hong, Jongsuk and Vesperini, Enrico and Askar, Abbas and Giersz, Mirek and Szkudlarek, Magdalena and Bulik, Tomasz},
  issn         = {0035-8711},
  language     = {eng},
  number       = {4},
  pages        = {5645--5656},
  publisher    = {Oxford University Press},
  series       = {Monthly Notices of the Royal Astronomical Society},
  title        = {Binary black hole mergers from globular clusters : The impact of globular cluster properties},
  url          = {http://dx.doi.org/10.1093/mnras/sty2211},
  doi          = {10.1093/mnras/sty2211},
  volume       = {480},
  year         = {2018},
}