http://arxiv.org/abs/1809.04126
We show that binaries of stellar-mass black holes formed inside a young proto-globular cluster, grow rapidly inside the cluster’s core by accretion of the intra-cluster gas, before the gas may be depleted from the core. During the mass increase, the binary gets hardened because of conservation of angular momentum in the case of isotropic accretion. The effect is stronger for softer binaries. Initially soft binaries can get hard, before dissolving due to three body encounters, and eventually merge within a Hubble time increasing the merger rate of binaries inside stellar clusters. This process provides an explanation for the high masses of binary black holes observed frequently by LIGO. It also indicates a novel formation and hardening channel.
Z. Roupas and D. Kazanas
Thu, 13 Sep 18
58/68
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