A Black Hole - White Dwarf Compact Binary Model for Long Gamma-ray Bursts without Supernova Association

TL;DR

This paper proposes a novel model where long gamma-ray bursts without supernovae are produced by unstable accretion in a black hole-white dwarf binary system, filling a gap in understanding such events.

Contribution

It introduces a new compact binary model involving a black hole and white dwarf to explain long GRBs without supernovae, expanding current astrophysical theories.

Findings

Suggests a new formation channel for long GRBs without supernovae.

Explains observations of certain low-redshift long GRBs lacking supernovae.

Provides a theoretical framework for unstable accretion in black hole-white dwarf systems.

Abstract

Gamma-ray bursts (GRBs) are luminous and violent phenomena in the universe. Traditionally, long GRBs are expected to be produced by the collapse of massive stars and associated with supernovae. However, some low-redshift long GRBs have no detection of supernova association, such as GRBs 060505, 060614 and 111005A. It is hard to classify these events convincingly according to usual classifications, and the lack of the supernova implies a non-massive star origin. We propose a new path to produce long GRBs without supernova association, the unstable and extremely violent accretion in a contact binary system consisting of a stellar-mass black hole and a white dwarf, which fills an important gap in compact binary evolution.