The astrophysical origin of observed low-mass compact binary coalescences in the 1-2. 5 M_ range remains ambiguous. Both binary neutron star (BNS) and binary low-mass black hole (LMBH) mergers produce nearly identical inspiral waveforms, and electromagnetic follow-up is not always possible. Distinguishing between these scenarios therefore presents a key challenge. We demonstrate that waveform differences in the late-inspiral to postmerger epochs create significant mismatches that will be detectable by planned detectors, viz. , NEMO, Cosmic Explorer, and Einstein Telescope, while the currently operational LIGO A+ will be effective only for nearby sources. These differences are enhanced for stiffer equations of state. We show how the redshift-dependent compact binary merger rate inferred from gravitational wave observations can be parsed into BNS and LMBH components, accounting for misclassification probability. We forecast model-independent 90% exclusion sensitivities for the LMBH fraction. Interpreting these LMBHs as dark matter capture-induced transmuted black holes, we convert exclusion sensitivities into projected exclusion bounds on heavy non-annihilating dark matter. Our results illustrate how gravitational wave measurements can disentangle compact object populations and provide new insights into particle dark matter interactions.
Bhattacharya et al. (Mon,) studied this question.