2008/06/25 by Michael Gill, Michele Trenti, M. Coleman Miller +3 · 4 citations
Physics and Astronomy · #Astronomy and Astrophysical Research #Astrophysical Phenomena and Observations #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/591269
15 pages, 3 figures, ApJ, in press
arxiv created 2008/06/25 · openalex publication_date 2008/10/07 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
In many theoretical scenarios it is expected that intermediate-mass black holes (IMBHs, with masses M ∼ 10 2 –10 4 M ☉ ) reside at the centers of some globular clusters. However, observational evidence for their existence is limited. Several previous numerical investigations have focused on the impact of an IMBH on the cluster dynamics or brightness profile. Here we instead present results from a large set of direct N -body simulations including single and binary stars. These show that there is a potentially more detectable IMBH signature, namely on the variation of the average stellar mass between the center and the half-light radius. We find that the existence of an IMBH quenches mass segregation and causes the average mass to exhibit only modest radial variation in collisionally relaxed star clusters. This differs from when there is no IMBH. To measure this observationally requires high-resolution imaging at the level of that already available from the Hubble Space Telescope ( HST ) for the cores of a large sample of Galactic globular clusters. With a modest additional investment of HST time to acquire fields around the half-light radius, it will be possible to identify the best candidate clusters to harbor an IMBH. This test can be applied only to globulars with a half-light relaxation time ≲1 Gyr, which is required to guarantee efficient energy equipartition due to two-body relaxation.