Binary neutron-star mergers will predominantly produce black-hole remnants of mass ∼3 - 4 M☉ , thus populating the putative low-mass gap between neutron stars and stellar-mass black holes. If these low-mass black holes are in dense astrophysical environments, mass segregation could lead to "second-generation" compact binaries merging within a Hubble time. In this paper, we investigate possible signatures of such low-mass compact binary mergers in gravitational-wave observations. We show that this unique population of objects, if present, will be uncovered by the third-generation gravitational-wave detectors, such as Cosmic Explorer and Einstein Telescope. Future joint measurements of chirp mass M and effective spin χeff could clarify the formation scenario of compact objects in the low-mass gap. As a case study, we show that the recent detection of GW190425 (along with GW170817) favors a double Gaussian mass model for neutron stars, under the assumption that the primary in GW190425 is a black hole formed from a previous binary neutron-star merger....
Bibliographical noteFunding Information:
We thank Simon Stevenson and Nathan Johnson-McDaniel for carefully reading the paper and providing useful comments and Surabhi Sachdev for discussion and comments. A. G. and B. S. S. are supported in part by NSF Grants No. PHY-1836779, No. AST-1716394, and No. AST-1708146. D. G. is supported by Leverhulme Trust Grant No. RPG-2019-350. K. G. A. is partially supported by the Swarnajayanti Fellowship Grant No. DST/SJF/PSA-01/2017-18 and a grant from Infosys Foundation. E. B. is supported by NSF Grants No. PHY-1841464 and No. AST-1841358, NSF-XSEDE Grant No. PHY-090003, NASA ATP Grant No. 17-ATP17-0225, and NASA ATP Grant No. 19-ATP19-0051. This research was supported in part by the NSF under Grant No. NSF PHY-1748958. E. B. acknowledges support from the Amaldi Research Center, funded by the MIUR program “Dipartimento di Eccellenza” (CUP: B81I18001170001) and thanks the physics department at the University of Rome “Sapienza” for hospitality during the completion of this work. This project has received funding from the EU H2020 research and innovation programme under the Marie Skłodowska-Curie Grant No. 690904. The authors acknowledge networking support by the COST Action CA16104 “GWverse.” Computational work was performed on the University of Birmingham’s BlueBEAR cluster, the Athena cluster at HPC Midlands+ funded by EPSRC Grant No. EP/P020232/1, the Maryland Advanced Research Computing Center, and the IUCAA LDG cluster Sarathi. The evaluation of was performed with the gwdet code available at . This document has LIGO preprint number P1900271 .
© 2020 American Physical Society.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)