Dynamical double black holes and their host cluster properties

Chattopadhyay, Debatri, Hurley, Jarrod, Stevenson, Simon and Raidani, Arihant 2022. Dynamical double black holes and their host cluster properties. Monthly Notices of the Royal Astronomical Society 513 (3) , 4527–4555. 10.1093/mnras/stac1163

PDF - Published Version Download (3MB)

Abstract

We investigate the relationship between the global properties of star clusters and their double black hole (DBH) populations. We use the code NBODY6 to evolve a suite of star cluster models with an initial mass of O(104)M⊙ and varying initial parameters. We conclude that cluster metallicity plays the most significant role in determining the lifespan of a cluster, while the initial half-mass radius is dominant in setting the rate of BH exchange interactions in the central cluster regions. We find that the mass of interacting BHs, rather than how frequently their interactions with other BHs occur, is more crucial in the thermal expansion and eventual evaporation of the cluster. We formulate a novel approach to easily quantify the degree of BH-BH dynamical activity in each model. We report 12 in-cluster and three out-of-cluster (after ejection from the cluster) DBH mergers, of different types (inspiral, eccentric, and hierarchical) across the 10 N-body models presented. Our DBH merger efficiency is 3–4 × 10−5 mergers per M⊙. We note the cluster initial density plays the most crucial role in determining the number of DBH mergers, with the potential presence of a transitional density point (between 1.2 and 3.8 × 103 M⊙ pc−3) below which the number of in-cluster mergers increases with cluster density and above which the increased stellar density acts to prevent in-cluster BH mergers. The importance of the history of dynamical interactions within the cluster in setting up the pathways to ejected DBH mergers is also discussed.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Physics and Astronomy
Publisher:	Royal Astronomical Society
ISSN:	0035-8711
Date of First Compliant Deposit:	19 May 2022
Date of Acceptance:	22 April 2022
Last Modified:	23 May 2023 23:27
URI:	https://orca.cardiff.ac.uk/id/eprint/149868

Citation Data

Cited 1 time in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item