Probing the low-luminosity GRB population with new generation satellite detectors

TL;DR

This paper compares detection capabilities of Swift, GLAST, and EXIST satellites for low-luminosity gamma-ray bursts, predicting increased detection rates and extended redshift horizons with future instruments, enhancing understanding of LL GRB populations.

Contribution

It provides a comparative analysis of current and future satellite detectors' ability to observe low-luminosity GRBs, including expected detection rates and redshift reach.

Findings

GLAST will double Swift's LL GRB detection rate.

EXIST will detect about 30 LL GRBs over 5 years.

Detection horizon for LL GRBs extends to z ≈ 1.1 with EXIST.

Abstract

We compare the detection rates and redshift distributions of low-luminosity (LL) GRBs localized by Swift with those expected to be observed by the new generation satellite detectors on GLAST (now Fermi) and, in future, EXIST. Although the GLAST burst telescope will be less sensitive than Swift's in the 15--150 keV band, its large field-of-view implies that it will double Swift's detection rate of LL bursts. We show that Swift, GLAST and EXIST should detect about 1, 2 & 30 LL GRBs, respectively, over a 5-year operational period. The burst telescope on EXIST should detect LL GRBs at a rate of more than an order of magnitude greater than that of Swift's BAT. We show that the detection horizon for LL GRBs will be extended from $z \simeq 0.4$ for Swift to $z \simeq 1.1$ in the EXIST era. Also, the contribution of LL bursts to the observed GRB redshift distribution will contribute to an identifiable feature in the distribution at $z \simeq 1$.