The global mass functions of 35 Galactic globular clusters - II. Clues on the initial mass function and black hole retention fraction

Baumgardt, H. and Sollima, S. (2017) The global mass functions of 35 Galactic globular clusters - II. Clues on the initial mass function and black hole retention fraction. Monthly Notices of the Royal Astronomical Society, 472 1: 744-750. doi:10.1093/mnras/stx2036

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Author Baumgardt, H.
Sollima, S.
Title The global mass functions of 35 Galactic globular clusters - II. Clues on the initial mass function and black hole retention fraction
Journal name Monthly Notices of the Royal Astronomical Society   Check publisher's open access policy
ISSN 0035-8711
1365-2966
Publication date 2017-08-12
Year available 2017
Sub-type Article (original research)
DOI 10.1093/mnras/stx2036
Open Access Status File (Publisher version)
Volume 472
Issue 1
Start page 744
End page 750
Total pages 7
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Abstract In this paper, we compare the mass function slopes of Galactic globular clusters recently determined by Sollima & Baumgardt with a set of dedicated N-body simulations of star clusters containing between 65 000 and 200 000 stars. We study clusters starting with a range of initial mass functions (IMFs), black hole retention fractions and orbital parameters in the parent galaxy. We find that the present-day mass functions of globular clusters agree well with those expected for star clusters starting with Kroupa or Chabrier IMFs, and are incompatible with clusters starting with single power-law mass functions for the low-mass stars. The amount of mass segregation seen in the globular clusters studied by Sollima & Baumgardt can be fully explained by two-body relaxation driven mass segregation from initially unsegregated star clusters. Based on the present-day global mass functions, we expect that a typical globular cluster in our sample has lost about 75 per cent of its mass since formation, while the most evolved clusters have already lost more than 90 per cent of their initial mass and should dissolve within the next 1-2 Gyr. Most clusters studied by Sollima & Baumgardt also show a large difference between their central and global mass function (MF) slopes, implying that the majority of Galactic globular clusters are either near or already past core collapse. The strong mass segregation seen in most clusters also implies that only a small fraction of all black holes formed in globular clusters still reside in them.
Keyword Methods: numerical – stars: luminosity function
Mass function – globular clusters: general
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ
Additional Notes This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Monthly Notices of the Royal Astronomical Society. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
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Created: Sat, 11 Nov 2017, 23:02:16 EST