Gamma-ray bursts and kilonovae from the accretion-induced collapse of white dwarfs

TL;DR

This paper presents advanced 2D simulations of white dwarf accretion-induced collapse, suggesting such events could produce gamma-ray bursts and kilonovae, and contribute to heavy element synthesis, under extreme magnetic and rotational conditions.

Contribution

First 2D general relativistic neutrino magnetohydrodynamic simulations of AIC in rapidly rotating, magnetized white dwarfs, exploring rare conditions potentially linked to observed gamma-ray bursts.

Findings

Systems can generate relativistic jets and neutron-rich outflows.

Results are consistent with properties of certain long gamma-ray bursts and kilonovae.

Highlights potential role of AIC in heavy r-process element production.

Abstract

We present the first seconds-long 2D general relativistic neutrino magnetohydrodynamic simulations of accretion-induced collapse (AIC) in rapidly rotating, strongly magnetized white dwarfs (WDs), which might originate as remnants of double-WD mergers. This study examines extreme combinations of magnetic fields and rotation rates, motivated both by the need to address the limitations of 2D axisymmetric simulations and to explore the physics of AIC under rare conditions that, while yet to be observationally confirmed, may be consistent with current theoretical models and account for unusual events. Under these assumptions, our results demonstrate that, if realizable, such systems can generate relativistic jets and neutron-rich outflows with properties consistent with long gamma-ray bursts (LGRBs) accompanied by kilonovae, such as GRB 211211A and GRB 230307A. These findings highlight the potential role of AIC in heavy $r$-process element production and offer a framework for understanding rare LGRBs associated with kilonova emission. Longer-duration 3D simulations are needed to fully capture magnetic field amplification, resolve instabilities, and determine the fate of the energy retained by the magnetar at the end of the simulations.