Extending the Search for Muon Neutrinos Coincident with Gamma-Ray Bursts in IceCube Data

Abstract

We present an all-sky search for muon neutrinos produced during the prompt γ-ray emission of 1172 gamma-ray bursts (GRBs) with the IceCube Neutrino Observatory. The detection of these neutrinos would constitute evidence for ultra-high-energy cosmic-ray (UHECR) production in GRBs, as interactions between accelerated protons and the prompt γ-ray field would yield charged pions, which decay to neutrinos. A previously reported search for muon neutrino tracks from northern hemisphere GRBs has been extended to include three additional years of IceCube data. A search for such tracks from southern hemisphere GRBs in five years of IceCube data has been introduced to enhance our sensitivity to the highest energy neutrinos. No significant correlation between neutrino events and observed GRBs is seen in the new data. Combining this result with previous muon neutrino track searches and a search for cascade signature events from all neutrino flavors, we obtain new constraints for single-zone fireball models of GRB neutrino and UHECR production.

A Search for Neutrino Emission from Fast Radio Bursts with Six Years of IceCube Data

“…The year-to-year event rate, 2-3.5 mHz, is lower than that of the northern samples mainly due to a higher energy threshold imposed to reduce background from atmospheric muons and the asymmetric separation of hemispheres, which makes the northern hemisphere ∼20% larger in solid angle than the southern (Aartsen et al 2017b). The southern samples are dominated by down-going atmospheric muons with median energy on the order of 10 TeV.…”

“…In the northern hemisphere, the Earth filters out cosmic-ray-induced atmospheric muons, so the data samples consist primarily of atmospheric muon neutrinos with a median energy on the order of 1 TeV. The event rate in the northern hemisphere increases from 3.5 mHz in the first year (Aartsen et al 2015e) to 6 mHz in later years (Aartsen et al 2017b), as shown in Figure 1. This year-to-year variation is due largely to two combined effects: first, the initial event selections treat each year of the IceCube data sample independently due to filter and data processing scheme updates in the early years of IceCube operation; second, each data sample was separately optimized for sensitivity to its corresponding set of GRBs.…”

“…The injected signal fluence (time-integrated flux, denoted as F) is found, which yields a certain probability of obtaining a certain significance in the background-only TS distribution (Neyman 1937;Aartsen et al 2017b). Specifically, sensitivity and discovery potential are defined as the minimum signal fluences required to surpass, respectively, the median in 90% of the trials and the 5σ point in 90% of the trials.…”

Constraints on Galactic Neutrino Emission with Seven Years of IceCube Data

“…Notably, blazars are constrained to contribute less than 27% of the flux for -E 2.5 or 50% if the spectrum is as hard as -E 2.2 (Aartsen et al 2017). Prompt emission from triggered gamma-ray bursts are strongly constrained to <1% contribution to the astrophysical flux (Aartsen et al 2017b). In the cases of starburst or star-forming galaxies, only a small percentage are cataloged.…”

Neutrino fluence from gamma-ray bursts: off-axis view of structured jets

“…A smoking-gun test of this scenario is the production of high-energy neutrinos from the decay of charged pions and kaons produced by CR interactions with the internal photon background (Waxman & Bahcall 1997;Guetta et al 2004;Zhang & Kumar 2013). Searches of neutrino emission of GRBs with the IceCube neutrino observatory at the South Pole has put meaningful constraints on the neutrino emission of GRBs (Ahlers et al 2011;Abbasi et al 2012;Aartsen et al 2017) and has triggered various model revisions Li 2012;Hummer et al 2012;He et al 2012;Murase & Ioka 2013;Senno et al 2016;Denton & Tamborra 2018).…”