Numerical Models of Blackbody-Dominated GRBs

TL;DR

This paper models blackbody-dominated gamma-ray bursts using relativistic hydrodynamics to understand their thermal emission, proposing a neutron star-helium core merger as the progenitor.

Contribution

It introduces detailed relativistic hydrodynamic simulations of jet propagation in a merger environment to explain BBD-GRB thermal signatures.

Findings

Thermal emission results from jet interaction with ejected hydrogen envelope.

Simulation reproduces observed thermal components of BBD-GRBs.

Proposes NS-He merger as a plausible progenitor for BBD-GRBs.

Abstract

Blackbody-dominated (BBD) gamma-ray bursts (GRBs) are events characterized by the absence of a typical afterglow, long durations and the presence of a significant thermal component following the prompt gamma-ray emission. GRB 101225A (the `Christmas burst') is a prototype of this class. A plausible progenitor system for it, and for the BBD-GRBs, is the merger of a neutron star (NS) and a helium core of an evolved, massive star. Using relativistic hydrodynamic simulations we model the propagation of an ultrarelativistic jet through the enviroment created by such a merger and we compute the whole radiative signature, both thermal and non-thermal, of the jet dynamical evolution. We find that the thermal emission originates from the interaction between the jet and the hydrogen envelope ejected during the NS/He merger.