TY - JOUR

T1 - Using gravitational waves to distinguish between neutron stars and black holes in compact binary mergers

AU - Brown, Stephanie M.

AU - Capano, Collin

AU - Krishnan, Badri

N1 - Funding Information: This research has made use of data, software, and/or web tools obtained from the LIGO Open Science Center ( https://losc.ligo.org ), a service of LIGO Laboratory, the LIGO Scientific Collaboration, and the Virgo Collaboration. LIGO is funded by the U.S. National Science Foundation. Virgo is funded by the French Centre National de Recherche Scientifique (CNRS), the Italian Istituto Nazionale della Fisica Nucleare (INFN), and the Dutch Nikhef, with contributions by Polish and Hungarian institutes. We thank Jonathon Thompson, Sumit Kumar, Sanjay Reddy, Ingo Tews, and Duncan Brown for their valuable discussions. Our computations used the ATLAS computing cluster at AEI Hannover ( https://www.aei.mpg.de/43564/atlas-computing-cluster ) funded by the Max Planck Society and the State of Niedersachsen, Germany.

PY - 2022/12/14

Y1 - 2022/12/14

N2 - In August 2017, the first detection of a binary neutron star merger, GW170817, made it possible to study neutron stars in compact binary systems using gravitational waves. Despite being the loudest (in terms of signal-to-noise ratio) gravitational wave detected to date, it was not possible to unequivocally determine that GW170817 was caused by the merger of two neutron stars instead of two black holes from the gravitational-wave data alone. That distinction was largely due to the accompanying electromagnetic counterpart. This raises the question: under what circumstances can gravitational-wave data alone, in the absence of an electromagnetic signal, be used to distinguish between different types of mergers? Here, we study whether a neutron-star--black-hole binary merger can be distinguished from a binary black hole merger using gravitational-wave data alone. We build on earlier results using chiral effective field theory to explore whether the data from LIGO and Virgo, LIGO A+, LIGO Voyager, or Cosmic Explorer could lead to such a distinction. The results suggest that the present LIGO-Virgo detector network will most likely be unable to distinguish between these systems even with the planned near-term upgrades. However, given an event with favorable parameters, third-generation instruments such as Cosmic Explorer will be capable of making this distinction. This result further strengthens the science case for third-generation detectors.

AB - In August 2017, the first detection of a binary neutron star merger, GW170817, made it possible to study neutron stars in compact binary systems using gravitational waves. Despite being the loudest (in terms of signal-to-noise ratio) gravitational wave detected to date, it was not possible to unequivocally determine that GW170817 was caused by the merger of two neutron stars instead of two black holes from the gravitational-wave data alone. That distinction was largely due to the accompanying electromagnetic counterpart. This raises the question: under what circumstances can gravitational-wave data alone, in the absence of an electromagnetic signal, be used to distinguish between different types of mergers? Here, we study whether a neutron-star--black-hole binary merger can be distinguished from a binary black hole merger using gravitational-wave data alone. We build on earlier results using chiral effective field theory to explore whether the data from LIGO and Virgo, LIGO A+, LIGO Voyager, or Cosmic Explorer could lead to such a distinction. The results suggest that the present LIGO-Virgo detector network will most likely be unable to distinguish between these systems even with the planned near-term upgrades. However, given an event with favorable parameters, third-generation instruments such as Cosmic Explorer will be capable of making this distinction. This result further strengthens the science case for third-generation detectors.

KW - gr-qc

KW - astro-ph.HE

UR - http://www.scopus.com/inward/record.url?scp=85144396258&partnerID=8YFLogxK

U2 - 10.48550/arXiv.2105.03485

DO - 10.48550/arXiv.2105.03485

M3 - Article

VL - 941

JO - The Astrophysical Journal

JF - The Astrophysical Journal

IS - 1

M1 - 98

ER -