# The Properties of a Black Hole-Neutron Star Merger Candidate

## TL;DR

This paper analyzes the properties and probabilities of a candidate black hole-neutron star merger detected via gravitational waves, focusing on estimating component masses and spins despite initial data limitations.

## Contribution

It introduces a method to estimate component masses and black hole spins for black hole-neutron star candidates with uncertain classifications.

## Key findings

- Probabilities for system categories (neutron star, black hole, mixed) are provided.
- Estimated component masses and spins for S190426c are derived.
- Method improves characterization of ambiguous gravitational wave signals.

## Abstract

The LIGO/Virgo Consortium (LVC) released a preliminary announcement of a candidate gravitational wave signal, S190426c, that could have arisen from a black hole-neutron star merger. As the first such candidate system, it's properties such as masses and spin are of great interest. Although LVC policy prohibits disclosure of these properties in preliminary announcements, LVC does release the estimated probabilities that this system is in specific categories, such as binary neutron star, binary black hole and black hole-neutron star. LVC also releases information concerning relative signal strength, distance, and the probability that ejected mass or a remnant disc survived the merger. In the case of events with a finite probability of being in more than one category, such as is likely to occur with a black hole-neutron star merger, it is shown how to estimate the masses of the components and the spin of the black hole. This technique is applied to the source S190426c.