Search for Neutron Star Binaries in the Local Group Galaxies Using LISA

TL;DR

This paper evaluates LISA's potential to detect neutron star binaries in local group galaxies, estimating detection rates and localization capabilities after a decade of observation.

Contribution

It provides the first estimates of LISA's ability to detect and localize neutron star binaries in nearby galaxies like LMC and M31.

Findings

LISA may detect about 5 NSBs in LMC and M31 within 10 years.

Some NSBs could be localized within the LMC.

Detected binaries can inform studies on r-process element origins.

Abstract

We discuss the prospects of LISA for detecting neutron star binaries (NSBs) in the local group galaxies such as LMC and M31. Using the recently estimated merger rate $ {\rm 1540 \, Gpc^{-3}yr^{-1}}$ and inversely applying the conventional arguments based on the $B$-band galaxy luminosities, we estimate the frequency distributions of NSBs in the local galaxies. We find that, after 10 year observation with its current design sensitivity, LISA might detect $\sim 5$ NSBs both in LMC and M31 with signal-to-noise ratios larger than 10. Some of the NSBs might be three-dimensionally localized well within LMC. These binaries will be useful for studying various topics including the origin of r-process elements.