The Swift short gamma-ray burst rate density: prospects for detecting binary neutron star mergers by aLIGO

TL;DR

This paper estimates the true rate density of short gamma-ray bursts (SGRBs) accounting for observational biases, and predicts the detection rates of binary neutron star mergers by advanced LIGO and Virgo, finding compatibility with existing models.

Contribution

It provides a bias-corrected SGRB rate density estimate and predicts binary neutron star merger detection rates for advanced gravitational wave detectors.

Findings

SGRB rate density is higher after bias correction.

Detection rates for LIGO/Virgo are between 1 and 180 per year.

Results align with pulsar observations and population synthesis models.

Abstract

Presently only 30% of short gamma ray bursts (SGRBs) have accurate redshifts, and this sample is highly biased by the limited sensitivity of {\it Swift} to detect SGRBs. We account for the dominant biases to calculate a realistic SGRB rate density out to $z = 0.5$ using the {\it Swift} sample of peak fluxes, redshifts, and those SGRBs with a beaming angle constraint from X-ray/optical observations. Assuming a significant fraction of binary neutron star mergers produce SGRBs, we calculate lower and upper detection rate limits of (1-180) per Yr by an advanced LIGO and Virgo coincidence search. Our detection rate is compatible with extrapolations using Galactic pulsar observations and population synthesis.