# Gravitational Collapse of Rotating Supermassive Stars including Nuclear Burning Effects

## TL;DR

This study simulates the collapse of rotating supermassive stars, finding that nuclear burning has minimal impact, and characterizes the resulting black hole, torus, and outflow properties relevant for astrophysical observations.

## Contribution

First axisymmetric simulation including nuclear burning effects in supermassive star collapse, analyzing the formation of black holes, tori, and outflows with detailed quantitative relations.

## Key findings

- Nuclear burning effects are negligible in realistic collapse scenarios.
- A rotating SMS core produces a torus and outflow with specific mass fractions.
- Outflows reach velocities of 0.2c and carry energies of 10^{54-56} erg.

## Abstract

Supermassive stars (SMSs) of mass $\gtrsim 10^5 M_\odot$ are candidates for seeds of supermassive black holes found in the center of many massive galaxies. We simulate the gravitational collapse of a rigidly rotating SMS core including nuclear burning effects in axisymmetric numerical-relativity simulation. We find that for realistic initial conditions, the nuclear burning does not play an important role. After the collapse, a torus surrounding a rotating black hole is formed and a fraction of the torus material is ejected. We quantitatively study the relation between the properties of these objects and rotation. We find that if a SMS core is sufficiently rapidly rotating, the torus and outflow mass have approximately $6\%$ and $1\%$ of the initial mass, respectively. The typical average velocity and the total kinetic energy of the outflow are $0.2~c$ and $10^{54-56}$ erg where $c$ is the speed of light. Finally, we briefly discuss the possibility for observing the torus and outflow.