Critical phenomena in the aspherical gravitational collapse of radiation fluids

TL;DR

This paper investigates critical phenomena in gravitational collapse of radiation fluids through numerical simulations, revealing universal critical solutions and decay of aspherical deviations, advancing understanding of black hole formation.

Contribution

It provides the first detailed numerical analysis of critical collapse in radiation fluids in both spherical and axisymmetric cases, demonstrating universality and decay of aspherical deviations.

Findings

Identification of the critical solution in spherical collapse.

Evidence for universality of the critical solution.

Decay of aspherical deviations in damped oscillations.

Abstract

We study critical phenomena in the gravitational collapse of a radiation fluid. We perform numerical simulations in both spherical symmetry and axisymmetry, and observe critical scaling in both supercritical evolutions, which lead to the formation of a black hole, and subcritical evolutions, in which case the fluid disperses to infinity and leaves behind flat space. We identify the critical solution in spherically symmetric collapse, find evidence for its universality, and study the approach to this critical solution in the absence of spherical symmetry. For the cases that we consider, aspherical deviations from the spherically symmetric critical solution decay in damped oscillations in a manner that is consistent with the behavior found by Gundlach in perturbative calculations. Our simulations are performed with an unconstrained evolution code, implemented in spherical polar coordinates, and adopting "moving-puncture" coordinates.