Hypernova and Gamma-Ray Burst Remnants as TeV Unidentified Sources

TL;DR

This paper explores hypernova and gamma-ray burst remnants as potential sources of TeV gamma-ray emissions, proposing new mechanisms and discussing observational signatures to identify their role among unidentified TeV sources.

Contribution

It introduces a novel gamma-ray emission process from radioactive isotopes in GRB/hypernova remnants and analyzes their potential as dominant contributors to TeV unidentified sources.

Findings

TeV gamma-ray sources could be dominated by GRB/hypernova remnants.

Proposes a new gamma-ray emission mechanism from radioactive isotopes.

Discusses observational signatures to distinguish emission mechanisms.

Abstract

We investigate hypernova (hyper-energetic supernova) and gamma-ray burst (GRB) remnants in our Galaxy as TeV gamma-ray sources, particularly in the role of potential TeV unidentified sources, which have no clear counterpart at other wavelengths. We show that the observed bright sources in the TeV sky could be dominated by GRB/hypernova remnants, even though they are fewer than supernova remnants (SNRs). If this is the case, TeV SNRs are more extended (and more numerous) than deduced from current observations. In keeping with their role as cosmic ray accelerators, we discuss hadronic gamma-ray emission from pi^0 decay, from beta decay followed by inverse Compton emission, and propose a third, novel process of TeV gamma-ray emission arising from the decay of accelerated radioactive isotopes such as 56Co entrained by relativistic or semi-relativistic jets in GRBs/hypernovae. We discuss the relevant observational signatures which could discriminate between these three mechanisms.