On LGRB progenitors: an approach from thermally-produced neutrinos

TL;DR

This paper explores how thermally-produced neutrinos can help identify the progenitors of long gamma-ray bursts, especially when electromagnetic signals are obscured or ambiguous.

Contribution

It introduces a neutrino-based method to distinguish between black hole and magnetar progenitors in GRBs, supplementing traditional electromagnetic observations.

Findings

Neutrino oscillation probabilities differ between progenitor types.

Estimated neutrino detection rates in Hyper-Kamiokande for GRB sources.

Neutrino signals can identify progenitors when EM signals are hidden or ambiguous.

Abstract

Gamma-ray bursts (GRB) are the most intense electromagnetic (EM) sources in the Universe. Long GRB (LGRB) correspond to those events with a typical prompt emission of more than a few seconds. It is generally assumed that they are originated after an implosion of a very massive star within a central compact object engine that can be either a black hole (BH) or a rapidly-spinning highly-magnetized neutron star (NS). Nevertheless, one of the most challenging aspects of defining a unique model is that the progenitor remains initially hidden for direct EM observation. In this work, we investigate the evolution of thermally-produced neutrino properties in both GRB progenitors to provide an alternative solution. We consider the characteristics of both progenitors and the fireball scenario to calculate the oscillation probabilities within a three-flavor admixture regime. Then we obtain the expected neutrino ratio and we also estimate the number of events from these sources that could be detected in the future Hyper-Kamiokande (Hyper-K) detector, considering a sample of previously observed GRB with remarkably signs of being magnetar-produced. Our findings indicate that examining the predicted neutrino rates result in an additional mechanism to determine the type of progenitor associated with these events. This is especially useful when, for instance, we cannot directly observe an electromagnetic counterpart, such as so-called "failed" GRB with hidden jets, or when light curve analysis is inconclusive.