Forecasting Gamma‐Ray Bursts Using Gravitational Waves

Abstract

The intriguing possibility of employing future ground-based gravitational-wave interferometers to forecast short gamma-ray bursts (GRBs) is explored. The forecasting prospect is quantified in terms of an advance-warning time: the binary-neutron star (BNS) inspiral time (to merger) from when the interferometer network accumulates a signal-to-noise ratio of 15. As sources for the Advanced LIGO-Virgo (ALV) network of 2020, BNS systems at luminosity distances of D ≤ 200 Mpc are considered, and similarly, BNS systems at D ≤ 1000 Mpc for Einstein Telescope. It is shown that the ALV network will provide a few minutes of warning time, thus will not forecast GRBs in the 2020s. On the other hand, Einstein Telescope will provide advance-warning times of more than 5 hours for D ≤ 100 Mpc. Taking 1 hour as a benchmark advance-warning time, a corresponding BNS range of roughly 600 Mpc is obtained for Einstein Telescope. Using current BNS event rates, it is shown that Einstein Telescope will forecast O(10 2 ) GRBs in the 2030s. This warning-time computation is reapplied to black hole-neutron star inspirals and it is found that one to three tidal disruption events are expected to be forecast by the same detector.

An Early-warning System for Electromagnetic Follow-up of Gravitational-wave Events

“…Cannon et al (2012) also discussed the expected rates of BNS events that could be detectable before merger and prospects for their localizations based on theoretical signal-to-noise ratio (S/N) and Fisher estimates. There have been other studies examining theoretical potentials of premerger BNS detections, such as Chu et al (2016) and Akcay (2019). In this Letter, for the first time, we show the implementation of a search that can detect BNSs premerger and provide early warnings to other observatories in practice; we examine the performance of GstLAL in recovering BNS systems before merger by running it over a month of simulated data with added signals.…”

Interpreting binary neutron star mergers: describing the binary neutron star dynamics, modelling gravitational waveforms, and analyzing detections

“…This will result in GW signals spending several cycles in the detector's band and much higher SNRs, BNS signals may spend up to hours in the bandwidth of the detector. As the signal enters the band much earlier, this will give the opportunity of early-warning alerts for possible EM counterparts [21]. However, the power spectrum of the detectors over the duration of each BNS signal may no longer be stationary, and, in addition, the rotation of the Earth during the period, while a BNS signal lasts in the detectors' bandwidths, may also bring in further subtleties in GW data analysis.…”

The Science Case for LIGO-India

“…The isolated blue contours correspond to the sources detected by AHL but not detected by HL. For a fraction of BNS events it will be possible to issue alerts up to δt ∼ 60 s before the epoch of merger [82,83,84]. Pre-merger or early warning detections will facilitate electromagnetic observations of the prompt emission, which encodes the initial conditions of the outflow and the state of the merger remnant.…”