Evolutionary origins of binary neutron star mergers: effects of common envelope efficiency and metallicity

Gallegos-Garcia, M., Berry, C. P. L. and Kalogera, V. (2023) Evolutionary origins of binary neutron star mergers: effects of common envelope efficiency and metallicity. Astrophysical Journal, 955(2), 133. (doi: 10.3847/1538-4357/ace434)

Abstract

The formation histories of compact binary mergers, especially stellar-mass binary black hole mergers, have recently come under increased scrutiny and revision. We revisit the question of the dominant formation channel and efficiency of forming binary neutron star (BNS) mergers. We use the stellar and binary evolution code MESA and implement a detailed method for common envelope and mass transfer. We perform simulations for donor masses between 7 M⊙ and 20 M⊙ with a neutron star (NS) companion of 1.4 M⊙ and 2.0 M⊙ at two metallicities, using varying common envelope efficiencies and two different prescriptions to determine if the donor undergoes core collapse or electron capture, given their helium and carbon–oxygen cores. In contrast to the case of binary black hole mergers, for an NS companion of 1.4 M⊙, all BNS mergers are formed following a common envelope phase. For an NS mass of 2.0 M⊙, we identify a small subset of mergers following only stable mass transfer if the NS receives a natal kick sampled from a Maxwellian distribution with velocity dispersion σ = 265 km s−1. Regardless of the supernova prescription, we find more BNS mergers at subsolar metallicity compared to solar.

• Item Type: Articles
• Additional Information: M.G.-G. is grateful for the support from the Ford Foundation Predoctoral Fellowship. C.P.L.B. acknowledges past support from the CIERA Board of Visitors Research Professorship and current support from the University of Glasgow. V.K. is supported by a CIFAR G+EU Senior Fellowship, by the Gordon and Betty Moore Foundation through grant GBMF8477, and by Northwestern University. This work utilized the computing resources at CIERA provided by the Quest high-performance computing facility at Northwestern University, which is jointly supported by the Office of the Provost, the Office for Research, and Northwestern University Information Technology, and used computing resources at CIERA funded by NSF PHY-1726951.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Berry, Dr Christopher
• Authors: Gallegos-Garcia, M., Berry, C. P. L., and Kalogera, V.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Research Centre: College of Science and Engineering > School of Physics and Astronomy > Institute for Gravitational Research
• Journal Name: Astrophysical Journal
• Publisher: IOP Publishing
• ISSN: 0004-637X
• ISSN (Online): 1538-4357
• Published Online: 26 September 2023
• Copyright Holders: Copyright © 2023 The Author(s)
• First Published: First published in Astrophysical Journal 955(2):133
• Publisher Policy: Reproduced under a Creative Commons license

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