Mapping Progenitors of Binary Black Holes and Neutron Stars with Binary Population Synthesis

TL;DR

This paper uses binary population synthesis to predict and analyze the progenitors of binary black holes and neutron stars, focusing on systems detectable via radial velocity variations, and assesses the observational strategies of the Milky Way Mapper.

Contribution

It introduces a method to identify potential progenitors of compact object binaries using population synthesis and evaluates the effectiveness of observational strategies in distinguishing different evolutionary models.

Findings

Wolf-Rayet stars or hot subdwarfs could be detectable progenitors.

Different mass loss and kick prescriptions mainly affect the number of detectable sources.

The Milky Way Mapper can potentially identify systems with compact remnants orbiting massive stars.

Abstract

The first directly observed gravitational wave event, GW150914, featuring the merger of two massive black holes, highlighted the need to determine how these systems of compact remnant binaries are formed. We use the binary population synthesis code COSMIC (Compact Object Synthesis and Monte Carlo Investigation Code) to predict the types of massive stars that will show significant radial velocity variations, indicative of a potential compact object (i.e. a black hole or neutron star) orbiting the star. We "observe" the binaries generated in the populations with a similar number of epochs and RV accuracy as planned for the Milky Way Mapper. In this analysis, we are especially interested in systems where a compact remnant is orbiting a massive O or B star as these systems survived the first supernova and neutron star kick. We test the ability of the Milky Way Mapper observing strategy to distinguish among different mass loss and kick prescriptions. We find that Wolf-Rayet stars or hot subdwarfs in binaries could be detectable (i.e. luminous, high delta RV max), viable progenitors of such objects, while the different prescriptions primarily affect the number of sources.