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arXiv · 1909.05804

Black holes in the low mass gap: Implications for gravitational wave observations

Anuradha Gupta·Davide Gerosa·K. G. Arun·Emanuele Berti·Will Farr·B. S. Sathyaprakash
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Abstract

Binary neutron-star mergers will predominantly produce black-hole remnants of mass $\sim 3-4\,M_{\odot}$, thus populating the putative \emph{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 ${\cal M}$ and effective spin $\chi_{\rm eff}$ 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.

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Anuradha Gupta, Davide Gerosa, K. G. Arun, Emanuele Berti, Will Farr, B. S. Sathyaprakash. 2019-09-12. Black holes in the low mass gap: Implications for gravitational wave observations. https://doi.org/10.1103/physrevd.101.103036

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