LISA sources in Milky Way globular clusters

TL;DR

This study predicts that Milky Way globular clusters contain approximately 21 LISA-detectable double-compact-object binaries, including black hole pairs, neutron star, and white dwarf combinations, some detectable at extragalactic distances.

Contribution

First comprehensive modeling of LISA sources in Milky Way globular clusters using 137 evolved cluster models matching observed properties.

Findings

Approximately 21 LISA-detectable sources in MW GCs.

Around 7 of these are black hole binaries.

Some sources could be detected in Andromeda or Virgo clusters.

Abstract

We explore the formation of double-compact-object binaries in Milky Way (MW) globular clusters (GCs) that may be detectable by the Laser Interferometer Space Antenna (LISA). We use a set of 137 fully evolved GC models that, overall, effectively match the properties of the observed GCs in the MW. We estimate that, in total, the MW GCs contain $\sim21$ sources that will be detectable by LISA. These detectable sources contain all combinations of black hole (BH), neutron star, and white dwarf components. We predict $\sim7$ of these sources will be BH-BH binaries. Furthermore, we show that some of these BH-BH binaries can have signal-to-noise ratios large enough to be detectable at the distance of the Andromeda galaxy or even the Virgo cluster.