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Title: The Formation of Rapidly Rotating Black Holes in High-mass X-Ray Binaries

In this paper, high-mass X-ray binaries (HMXRBs), such as Cygnus X-1, host some of the most rapidly spinning black holes (BHs) known to date, reaching spin parameters $$a\gtrsim 0.84$$. However, there are several effects that can severely limit the maximum BH spin parameter that could be obtained from direct collapse, such as tidal synchronization, magnetic core-envelope coupling, and mass loss. Here, we propose an alternative scenario where the BH is produced by a failed supernova (SN) explosion that is unable to unbind the stellar progenitor. A large amount of fallback material ensues, whose interaction with the secondary naturally increases its overall angular momentum content, and therefore the spin of the BH when accreted. Through SPH hydrodynamic simulations, we studied the unsuccessful explosion of an $$8\,{M}_{\odot }$$ pre-SN star in a close binary with a $$12\,{M}_{\odot }$$ companion with an orbital period of ≈1.2 days, finding that it is possible to obtain a BH with a high spin parameter $$a\gtrsim 0.8$$ even when the expected spin parameter from direct collapse is $$a\lesssim 0.3$$. This scenario also naturally explains the atmospheric metal pollution observed in HMXRB stellar companions.
 [1] ; ORCiD logo [1] ; ORCiD logo [2]
  1. Univ. of California, Santa Cruz, CA (United States)
  2. The Univ. of Arizona, Tucson, AZ (United States); Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 2041-8213
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 846; Journal Issue: 2; Journal ID: ISSN 2041-8213
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; binaries: close; supernovae: general
OSTI Identifier: