A consistent estimate for Gravitational Wave and Electromagnetic transient rates

TL;DR

This paper develops a unified model to estimate the rates of gravitational wave and electromagnetic transients from stellar remnants, aligning well with current observations and providing a basis for future constraints.

Contribution

It introduces a comprehensive stellar population synthesis approach to simultaneously estimate rates of various stellar transients and gravitational wave events.

Findings

Rates agree with current observational constraints.

Predicted gravitational wave merger rates match LIGO estimates.

Highlights need for tighter constraints to understand evolution and progenitor properties.

Abstract

Gravitational wave transients, resulting from the merger of two stellar remnants, are now detectable. The properties and rates of these directly relates to the stellar population which gave rise to their progenitors, and thus to other, electromagnetic transients which result from stellar death. We aim to estimate simultaneously the event rates and delay time distribution of gravitational wave-driven compact object mergers together with the rates of core collapse and thermonuclear supernovae within a single consistent stellar population synthesis paradigm. We combine event delay-time distributions at different metallicities from the Binary Population and Spectral Synthesis (BPASS) models with an analytic model of the volume-averaged cosmic star formation rate density and chemical evolution to determine the volume-averaged rates of each event rate at the current time. We estimate rates in excellent agreement with extant observational constraints on core-collapse supernovae, thermonuclear supernovae and long GRBs. We predict rates for gravitational wave mergers based on the same stellar populations, and find rates consistent with current LIGO estimates. We note that tighter constraints on the rates of these events will be required before it is possible to determine their redshift evolution, progenitor metallicity dependence or constrain uncertain aspects of stellar evolution.