High energy neutrino early afterglows from gamma-ray bursts revisited

TL;DR

This paper revisits high energy neutrino emission from gamma-ray burst early afterglows, analyzing different models and implications for future neutrino detector observations, with potential insights into baryon acceleration and afterglow mechanisms.

Contribution

It provides a comparative analysis of neutrino emission predictions from different GRB early afterglow models and discusses their detectability with future neutrino observatories.

Findings

Neutrino signals are more detectable under the late prompt emission model.

Detection likelihood is low for the reverse-forward shock model.

Early afterglow neutrino background could be comparable to prompt emission at very high energies.

Abstract

The high energy neutrino emission from gamma-ray bursts (GRBs) has been expected in various scenarios. In this paper, we study the neutrino emission from early afterglows of GRBs, especially under the reverse-forward shock model and late prompt emission model. In the former model, the early afterglow emission occurs due to dissipation made by an external shock with the circumburst medium (CBM). In the latter model, internal dissipation such as internal shocks produces the shallow decay emission in early afterglows. We also discuss implications of recent Swift observations for neutrino signals in detail. Future neutrino detectors such as IceCube may detect neutrino signals from early afterglows, especially under the late prompt emission model, while the detection would be difficult under the reverse-forward shock model. Contribution to the neutrino background from the early afterglow emission may be at most comparable to that from the prompt emission unless the outflow making the early afterglow emission loads more nonthermal protons, and it may be important in the very high energies. Neutrino-detections are inviting because they could provide us with not only information on baryon acceleration but also one of the clues to the model of early afterglows. Finally, we compare various predictions for the neutrino background from GRBs, which are testable by future neutrino-observations.