Searches for Neutrinos from Gamma-Ray Bursts using the IceCube Neutrino Observatory

TL;DR

This study extended the search for neutrinos from gamma-ray bursts over longer time windows using IceCube data, but found no correlation, setting limits on GRBs' contribution to the diffuse neutrino flux.

Contribution

It introduces extended time window analyses for neutrino-GRB correlation, broadening the scope beyond prompt emission.

Findings

No significant neutrino-GRB correlation detected.

Limits placed on GRBs' contribution to diffuse neutrino flux.

Prompt neutrino emission from GRBs is constrained to less than 1% of the diffuse flux.

Abstract

Gamma-ray bursts (GRBs) are considered as promising sources of ultra-high-energy cosmic rays (UHECRs) due to their large power output. Observing a neutrino flux from GRBs would offer evidence that GRBs are hadronic accelerators of UHECRs. Previous IceCube analyses, which primarily focused on neutrinos arriving in temporal coincidence with the prompt gamma rays, found no significant neutrino excess. The four analyses presented in this paper extend the region of interest to 14 days before and after the prompt phase, including generic extended time windows and targeted precursor searches. GRBs were selected between May 2011 and October 2018 to align with the data set of candidate muon-neutrino events observed by IceCube. No evidence of correlation between neutrino events and GRBs was found in these analyses. Limits are set to constrain the contribution of the cosmic GRB population to the diffuse astrophysical neutrino flux observed by IceCube. Prompt neutrino emission from GRBs is limited to $\lesssim$1% of the observed diffuse neutrino flux, and emission on timescales up to $10^4$ s is constrained to 24% of the total diffuse flux.