Constraints On Short, Hard Gamma-Ray Burst Beaming Angles From Gravitational Wave Observations

Understand

The first detection of a binary neutron star merger, GW170817, and an associated short gamma-ray burst confirmed that neutron star mergers are responsible for at least some of these bursts.

• The prompt gamma ray emission from these events is thought to be highly relativistically beamed.
• We present a method for inferring limits on the extent of this beaming by comparing the number of short gamma-ray bursts observed electromagnetically to the number of neutron star binary mergers detected in gravitational waves.
• We demonstrate that an observing run comparable to the expected Advanced LIGO 2016--2017 run would be capable of placing limits on the beaming angle of approximately $\theta \in (2.88^\circ,14.15^\circ)$, given one binary neutron star detection.