Neutrino and cosmic-ray emission from multiple internal shocks in gamma-ray bursts

TL;DR

This paper explores how multiple internal shocks in gamma-ray bursts produce neutrinos and cosmic rays at different radii, offering new insights into the structure and evolution of GRB outflows through multi-messenger observations.

Contribution

It introduces a model considering multiple emission regions in GRBs, expanding beyond single-zone models to better explain neutrino and cosmic-ray production.

Findings

Different messengers originate from different collision radii.

Multi-messenger observations can reveal the evolving structure of GRB outflows.

Multiple internal shocks contribute to high-energy particle emissions.

Abstract

Gamma-ray bursts are short-lived, luminous explosions at cosmological distances, thought to originate from relativistic jets launched at the deaths of massive stars. They are among the prime candidates to produce the observed cosmic rays at the highest energies. Recent neutrino data have, however, started to constrain this possibility in the simplest models with only one emission zone. In the classical theory of gamma-ray bursts, it is expected that particles are accelerated at mildly relativistic shocks generated by the collisions of material ejected from a central engine. We consider neutrino and cosmic-ray emission from multiple emission regions since these internal collisions must occur at very different radii, from below the photosphere all the way out to the circumburst medium, as a consequence of the efficient dissipation of kinetic energy. We demonstrate that the different messengers originate from different collision radii, which means that multi-messenger observations open windows for revealing the evolving GRB outflows.