Linking Short Gamma Ray Bursts and their Host Galaxies

TL;DR

This paper investigates the relationship between short gamma-ray burst (SGRB) luminosities and their host galaxy properties, revealing a significant anticorrelation that suggests possible distinct progenitor groups or a continuous distribution.

Contribution

It identifies and analyzes a significant anticorrelation between SGRB luminosities and host galaxy luminosities, proposing potential explanations involving progenitor populations and binary neutron star properties.

Findings

Luminosity of host galaxies anticorrelates with SGRB energy and luminosity.

Selection effects strengthen the observed correlation.

Binary neutron star mass effects can produce similar correlations.

Abstract

The luminosities of short gamma ray burst host galaxies are anticorrelated with both the isotropic equivalent gamma ray energy and the gamma ray luminosity of the explosions. Observational selection effects only strengthen the significance of this correlation. The correlation may indicate that there are two physically distinct groups of SGRBs. If so, it requires that the more luminous class of explosions be associated with the younger class of progenitors. Alternatively, it could be due to a continuous distribution of burst and host properties. As one possible explanation, we find that the effect of binary neutron star masses on inspiral time and energy reservoir produces a correlation of the appropriate sign, but does not automatically reproduce the correlation slope or the full range of SGRB energy scales. Any future model of SGRB progenitors needs to reproduce this correlation.