GRBs on probation: testing the UHE CR paradigm with IceCube

TL;DR

This paper tests the hypothesis that gamma-ray bursts are the sources of ultra-high-energy cosmic rays by analyzing neutrino flux data from IceCube, challenging the GRB origin model with observational limits.

Contribution

It introduces an alternative method linking the diffuse neutrino flux from all GRBs directly to cosmic ray measurements, providing a new way to test the GRB-UHECR connection.

Findings

IceCube's sensitivity constrains the GRB-UHECR hypothesis.

Diffuse neutrino flux limits challenge the GRB origin of cosmic rays.

The proposed approach relates neutrino fluxes directly to cosmic ray data.

Abstract

Gamma ray burst (GRB) fireballs provide one of very few astrophysical environments where one can contemplate the acceleration of cosmic rays to energies that exceed 10^20 eV. The assumption that GRBs are the sources of the observed cosmic rays generates a calculable flux of neutrinos produced when the protons interact with fireball photons. With data taken during construction IceCube has already reached a sensitivity to observe neutrinos produced in temporal coincidence with individual GRBs provided that they are the sources of the observed extragalactic cosmic rays. We here point out that the GRB origin of cosmic rays is also challenged by the IceCube upper limit on a possible diffuse flux of cosmic neutrinos which should not be exceeded by the flux produced by all GRB over Hubble time. Our alternative approach has the advantage of directly relating the diffuse flux produced by all GRBs to measurements of the cosmic ray flux. It also generates both the neutrino flux produced by the sources and the associated cosmogenic neutrino flux in a synergetic way.