Intermediate-Mass Black Holes in binary-rich star clusters

Abstract

There is both theoretical expectation and some observational clues that intermediate mass black holes reside in nuclei of globular clusters. In order to find an independent indicator for their existence, we investigate in this paper how an IMBH manifests itself through its dynamical interaction with a binary rich globular cluster of moderate extension and mass. By means of direct $N$-body integration we follow the dynamical evolution of models of such a system over a time span of $\approx$ 0.8 Gyr and compare the cases with and without the primordial binaries as well as with and without the IMBH. In accord with previous results, we show that when present the IMBH develops a power-law density cusp of stars around it, regardless of the binary population in the cluster. If, however, binaries are present, their interaction with the IMBH leads to the production of high velocity escapers at a rate of the order of 0.1 Myr${}^{-1}$. These stars may contribute to the population of high-velocity stars observed in the Galaxy. Clusters hosting the IMBH together with high number of binaries also form a denser halo of marginally unbound stars than clusters that lack either the IMBH or the rich binary population. Finally, we show that the binary population leads to an increased rate of direct interactions of stars with the IMBH, potentially observable as tidal disruption events.

14 pages, 7 figures, accepted for publication in MNRAS, corrected sectioning

References in corpus (19)

• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• The Initial-Final Mass Relation: Direct Constraints at the Low Mass End
• Interaction of massive black hole binaries with their stellar environment: I. Ejection of hypervelocity stars
• N-body modeling of globular clusters: Masses, mass-to-light ratios and intermediate-mass black holes
• The fraction of binary systems in the core of thirteen low-density Galactic globular clusters
• Hypervelocity Stars: Predicting the Spectrum of Ejection Velocities
• Ratios of star cluster core and half-mass radii: a cautionary note on intermediate-mass black holes in star clusters
• Simulated Dark-Matter Halos as a Test of Nonextensive Statistical Mechanics
• On the coexistence of stellar-mass and intermediate-mass black holes in globular clusters
• Star Clusters with Primordial Binaries: I. Dynamical Evolution of Isolated Models
• Star Clusters with Primordial Binaries: III. Dynamical Interaction between Binaries and an Intermediate Mass Black Hole
• Star Clusters with Primordial Binaries: II. Dynamical Evolution of Models in a Tidal Field
• Intermediate Mass Black Hole Induced Quenching of Mass Segregation in Star Clusters
• The presence of intermediate-mass black holes in globular clusters and their connection with extreme horizontal branch stars
• Predicted Space Motions for Hypervelocity and Runaway Stars: Proper Motions and Radial Velocities for the GAIA Era
• A new method to create initially mass segregated star clusters in virial equilibrium
• The Nearest High-Velocity Stars Revealed by LAMOST Data Release 1
• Tidal breakup of triple stars in the Galactic Centre
• The properties of hypervelocity stars and S-stars originating from an eccentric disc around a supermassive black hole