The Impact of a Supernova Explosion in a Very Massive Binary

TL;DR

This study uses 3D hydrodynamic simulations to show that black hole accretion discs in very massive Population III binaries can survive supernova explosions of companion stars, potentially serving as long-lived ionizing sources in the early universe.

Contribution

It demonstrates through simulations that a significant portion of a black hole's accretion disc can survive a supernova explosion in a very massive binary, highlighting the potential longevity of such discs.

Findings

A large part of the accretion disc remains intact after supernova explosion.

Even with high explosion energy, about half of the disc can survive.

Surviving discs could contribute to cosmic reionization in the early universe.

Abstract

We consider the effect of a supernova (SN) explosion in a very massive binary that is expected to form in a portion of Population III stars with the mass higher than 100$M_\odot$. In a Population III binary system, a more massive star can result in the formation of a BH and a surrounding accretion disc. Such BH accretion could be a significant source of the cosmic reionization in the early universe. However, a less massive companion star evolves belatedly and eventually undergoes a SN explosion, so that the accretion disc around a BH might be blown off in a lifetime of companion star. In this paper, we explore the dynamical impact of a SN explosion on an accretion disc around a massive BH, and elucidate whether the BH accretion disc is totally demolished or not. For the purpose, we perform three-dimensional hydrodynamic simulations of a very massive binary system, where we assume a BH of $10^3 M_{\odot}$ that results from a direct collapse of a very massive star and a companion star of $100 M_{\odot}$ that undergoes a SN explosion. We calculate the remaining mass of a BH accretion disc as a function of time. As a result, it is found that a significant portion of gas disc can survive through three-dimensional geometrical effects even after the SN explosion of a companion star. Even if the SN explosion energy is higher by two orders of magnitude than the binding energy of gas disc, about a half of disc can be left over. The results imply that the Population III BH accretion disc can be a long-lived luminous source, and therefore could be an important ionizing source in the early universe.