Ultra-High Energy Neutrino Afterglows of nearby Long Duration Gamma-Ray Bursts

TL;DR

This study models ultra-high energy neutrino production from nearby long-duration gamma-ray bursts using afterglow data, assessing their detectability with current and future neutrino observatories.

Contribution

It provides a detailed afterglow-based modeling approach to estimate UHE neutrino fluxes from nearby GRBs, incorporating different environmental models.

Findings

Realistic flux models suggest neutrino detection from these GRBs is unlikely in the foreseeable future.

The fitted blast wave parameters enable better understanding of UHECR acceleration in GRB environments.

Detection prospects with current detectors are limited based on the modeled fluxes.

Abstract

Detection of ultra-high energy (UHE, $\gtrsim 1$ PeV) neutrinos from astrophysical sources will be a major advancement in identifying and understanding the sources of UHE cosmic rays (CRs) in nature. Long duration gamma-ray burst (GRB) blast waves have been considered as potential acceleration sites of UHECRs. These CRs are expected to interact with GRB afterglow photons, which is synchrotron radiation from relativistic electrons co-accelerated with CRs in the blast wave, and naturally produce UHE neutrinos. Fluxes of these neutrinos are uncertain, however, and crucially depend on the observed afterglow modeling. We have selected a sample of 23 long duration GRBs within redshift 0.5 for which adequate electromagnetic afterglow data are available and which could produce high flux of UHE afterglow neutrinos, being nearby. We fit optical, X-ray and $\gamma$-ray afterglow data with an adiabatic blast wave model in a constant density interstellar medium and in a wind environment where the density of the wind decreases as inverse square of the radius from the center of the GRB. The blast wave model parameters extracted from these fits are then used for calculating UHECR acceleration and $p\gamma$ interactions to produce UHE neutrino fluxes from these GRBs. We have also explored the detectability of these neutrinos by currently running and upcoming large area neutrino detectors, such as the Pierre Auger Observatory, IceCube Gen-2 and KM3NeT observatories. We find that our realistic flux models from nearby GRBs will be unconstrained in foreseeable future.