A method to constrain mass and spin of GRB black hole within the NDAF model

TL;DR

This paper introduces a method to estimate the mass and spin of black holes in gamma-ray bursts using the neutrino-dominated accretion flow model, applied to GRB 101219B, providing new constraints on black hole properties.

Contribution

The paper develops a novel approach to constrain black hole mass and spin within the NDAF model, applied to a specific GRB with thermal emission data.

Findings

Estimated black hole mass: 5-9 solar masses

Black hole spin parameter: greater than 0.6

Disk mass: 3-4 solar masses

Abstract

Black holes (BHs) hide themselves behind various astronomical phenomena, and their properties, i.e., mass and spin, are usually difficult to constrain. One leading candidate for the central engine model of gamma-ray bursts (GRBs) invokes a stellar mass BH and a neutrino-dominated accretion flow (NDAF), with the relativistic jet launched due to neutrino-anti-neutrino annihilations. Such a model gives rise to a matter-dominated fireball, and is suitable to interpret GRBs with a dominant thermal component with a photospheric origin. We propose a method to constrain BH mass and spin within the framework of this model, and apply the method to a thermally-dominant GRB 101219B whose initial jet launching radius $r_0$ is constrained from the data. Using our numerical model of NDAF jets, we estimate the following constraints on the central BH: mass $M_{\rm BH} \sim 5-9~M_\odot$, spin parameter $a_* \gtrsim 0.6$, and disk mass $3~M_\odot \lesssim M_{\rm disk} \lesssim 4~M_\odot$. Our results also suggest that the NDAF model is a competitive candidate for the central engine of GRBs with a strong thermal component.