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Using binaries in Globular Clusters to catch sight of Intermediate-Mass Black Holes

Aros, Francisco I ; Sippel, Anna C ; Mastrobuono-battisti, Alessandra LU ; Bianchini, Paolo ; Askar, Abbas LU orcid and Van De Ven, Glenn (2021) In Monthly Notices of the Royal Astronomical Society 508(3). p.4385-4398
Abstract
The dynamical evolution of globular clusters (GCs) is tied to their binary population, as binaries segregate to the cluster centre, leading to an increased binary fraction in the core. This central overabundance of mainly hard binaries can serve as a source of energy for the cluster and has a significant effect on the observed kinematics, such as artificially increasing the observed line-of-sight velocity dispersion. We analyse the binary fractions and distributions of 95 simulated GCs, with and without an intermediate-mass black hole (IMBH) in their centre. We show that an IMBH will not only halt the segregation of binaries towards the cluster centre, but also, directly and indirectly, disrupt the binaries that segregate, thus, depleting... (More)
The dynamical evolution of globular clusters (GCs) is tied to their binary population, as binaries segregate to the cluster centre, leading to an increased binary fraction in the core. This central overabundance of mainly hard binaries can serve as a source of energy for the cluster and has a significant effect on the observed kinematics, such as artificially increasing the observed line-of-sight velocity dispersion. We analyse the binary fractions and distributions of 95 simulated GCs, with and without an intermediate-mass black hole (IMBH) in their centre. We show that an IMBH will not only halt the segregation of binaries towards the cluster centre, but also, directly and indirectly, disrupt the binaries that segregate, thus, depleting binaries in the cluster core. We illustrate this by showing that clusters with an IMBH have fewer binaries and flatter radial binary distributions than their counterparts without one. These differences in the binary fraction and distribution provide an additional indicator for the presence of a central IMBH in GCs. In addition, we analyse the effects of the binary fraction on the line-of-sight velocity dispersion in the simulated GCs and find that binaries can cause an overestimation of up to 70percent of the velocity dispersion within the core radius. Using recent VLT/MUSE observations of NGC 3201 by Giesers et al. (2019), we find an overestimation of 32.2±7.8percent in the velocity dispersion that is consistent with the simulations and illustrates the importance of accurately accounting for the binary population when performing kinematic or dynamical analysis. (Less)
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author
; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Monthly Notices of the Royal Astronomical Society
volume
508
issue
3
pages
14 pages
publisher
Oxford University Press
external identifiers
  • scopus:85119521866
ISSN
1365-2966
DOI
10.1093/mnras/stab2872
language
English
LU publication?
yes
id
e7f088fa-5951-4f8c-8121-ede557a43ef0
date added to LUP
2021-10-20 01:07:41
date last changed
2025-04-04 14:52:23
@article{e7f088fa-5951-4f8c-8121-ede557a43ef0,
  abstract     = {{The dynamical evolution of globular clusters (GCs) is tied to their binary population, as binaries segregate to the cluster centre, leading to an increased binary fraction in the core. This central overabundance of mainly hard binaries can serve as a source of energy for the cluster and has a significant effect on the observed kinematics, such as artificially increasing the observed line-of-sight velocity dispersion. We analyse the binary fractions and distributions of 95 simulated GCs, with and without an intermediate-mass black hole (IMBH) in their centre. We show that an IMBH will not only halt the segregation of binaries towards the cluster centre, but also, directly and indirectly, disrupt the binaries that segregate, thus, depleting binaries in the cluster core. We illustrate this by showing that clusters with an IMBH have fewer binaries and flatter radial binary distributions than their counterparts without one. These differences in the binary fraction and distribution provide an additional indicator for the presence of a central IMBH in GCs. In addition, we analyse the effects of the binary fraction on the line-of-sight velocity dispersion in the simulated GCs and find that binaries can cause an overestimation of up to 70percent of the velocity dispersion within the core radius. Using recent VLT/MUSE observations of NGC 3201 by Giesers et al. (2019), we find an overestimation of 32.2±7.8percent in the velocity dispersion that is consistent with the simulations and illustrates the importance of accurately accounting for the binary population when performing kinematic or dynamical analysis.}},
  author       = {{Aros, Francisco I and Sippel, Anna C and Mastrobuono-battisti, Alessandra and Bianchini, Paolo and Askar, Abbas and Van De Ven, Glenn}},
  issn         = {{1365-2966}},
  language     = {{eng}},
  month        = {{10}},
  number       = {{3}},
  pages        = {{4385--4398}},
  publisher    = {{Oxford University Press}},
  series       = {{Monthly Notices of the Royal Astronomical Society}},
  title        = {{Using binaries in Globular Clusters to catch sight of Intermediate-Mass Black Holes}},
  url          = {{http://dx.doi.org/10.1093/mnras/stab2872}},
  doi          = {{10.1093/mnras/stab2872}},
  volume       = {{508}},
  year         = {{2021}},
}