GRB 190829A -- A Showcase of Binary Late Evolution

TL;DR

This paper models GRB 190829A as a binary-driven hypernova, explaining its multiwavelength emissions through the collapse of a CO star and neutron star interactions, supported by extensive observational data.

Contribution

It provides a detailed physical model of GRB 190829A within the BdHN II framework, linking binary evolution to observed gamma-ray burst features.

Findings

Consistent explanation of double prompt pulses and afterglows with the BdHN II model.

Identification of binary system components as CO star and neutron star.

Modeling of physical processes matching multiwavelength observational data.

Abstract

GRB 190829A is the fourth closest gamma-ray burst (GRB) to date ($z=0.0785$). Owing to its wide range of radio, optical, X-ray, and the very-high-energy (VHE) observations by H.E.S.S., it has become an essential new source examined by various models with complementary approaches. We here show in GRB 190829A the double-prompt pulses and the three-multiwavelength afterglows are consistent with the type II binary-driven hypernova (BdHN II) model. The progenitor is a binary composed of a carbon-oxygen (CO) star and a neutron star (NS) companion. The gravitational collapse of the iron core of the CO star produces a supernova (SN) explosion and leaves behind a new neutron star ($\nu$NS) at its center. The accretion of the SN ejecta onto the NS companion and onto the $\nu$NS via matter fallback spins up the NSs and produces the double-peak prompt emission. The synchrotron emission from the expanding SN ejecta with the energy injection from the rapidly spinning $\nu$NS and its subsequently spin-down leads to the afterglow in the radio, optical, and X-ray. We model the sequence of physical and related radiation processes in BdHNe and focus on individuating the binary properties that play the relevant roles.