A case study of GW190425 for classifying binary neutron star versus binary black hole mergers and constraining asymmetric dark matter with gravitational wave detectors

TL;DR

This study explores the classification of GW190425 as a binary neutron star or black hole merger, examines dark matter implications, and assesses future detector capabilities for accurate event classification and dark matter constraints.

Contribution

It introduces a simulation-based analysis of GW190425-like events with future gravitational wave detectors and evaluates their ability to classify such events and constrain dark matter properties.

Findings

A+ sensitivity networks cannot confidently classify GW190425-like events.

A# sensitivity and next-generation detectors can classify events with a stiff equation of state.

Future detectors can improve dark matter parameter constraints from gravitational wave observations.

Abstract

The LIGO Scientific, Virgo, and KAGRA collaboration has identified two binary neutron star merger candidates, GW170817 and GW190425, along with several binary black hole candidates. While GW170817 was confirmed as a BNS merger through its electromagnetic counterparts, GW190425 lacked such observations, leaving its classification uncertain. We examine the possibility that GW190425 originated from black holes that merged after dark matter accretion caused their progenitor neutron stars to implode. Using this event, we place constraints on dark matter parameters, such as its mass and interaction cross section. We simulate GW190425-like events and analyze them using future gravitational wave detector networks, including upcoming upgrades to current detector networks and next-generation observatories. We show that a network with A+ sensitivity can not classify a GW190425-like event with sufficient confidence. Detector networks with A# sensitivity can classify such events only if the neutron stars follow a relatively stiff equation of state, whose stronger tidal imprint differs measurably from a binary black hole waveform. Next-generation observatories like the Einstein Telescope and Cosmic Explorer recover the tidal signature even for soft, compact stars, enabling confident classification. Finally, we forecast the dark matter constraints that future gravitational wave networks could achieve for similar events.