Effects of intermediate mass black holes on nuclear star clusters

Journal Article · Thu Nov 20 04:00:00 EST 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/796/1/40· OSTI ID:22369977

Mastrobuono-Battisti, Alessandra; Perets, Hagai B. ^[1]; Loeb, Abraham ^[2]

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1. Physics Department, Technion-Israel Institute of Technology, Haifa 32000 (Israel)
2. Institute for Theory and Computation, Harvard University, 60 Garden Street, Cambridge, MA 02138 (United States)

Nuclear star clusters (NSCs) are dense stellar clusters observed in galactic nuclei, typically hosting a central massive black hole. Here we study the possible formation and evolution of NSCs through the inspiral of multiple star clusters hosting intermediate mass black holes (IMBHs). Using an N-body code, we examine the dynamics of the IMBHs and their effects on the NSC. We find that IMBHs inspiral to the core of the newly formed NSC and segregate there. Although the IMBHs scatter each other and the stars, none of them is ejected from the NSC. The IMBHs are excited to high eccentricities and their radial density profile develops a steep power-law cusp. The stars also develop a power-law cusp (instead of the central core that forms in their absence), but with a shallower slope. The relaxation rate of the NSC is accelerated due to the presence of IMBHs, which act as massive perturbers. This in turn fills the loss cone and boosts the tidal disruption rate of stars both by the MBH and the IMBHs to a value excluded by rate estimates based on current observations. Rate estimates of tidal disruptions can therefore provide a cumulative constraint on the existence of IMBHs in NSCs.

• OSTI ID: 22369977
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 796; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BLACK HOLES
DENSITY
GALAXIES
GALAXY NUCLEI
LOSS CONE
MASS
RELAXATION
STAR CLUSTERS
STAR EVOLUTION
STARS