Challenging the paradigm of singularity excision in gravitational collapse

TL;DR

This paper demonstrates that avoiding singularity excision in 3D simulations of rotating star collapse enhances stability and enables extended gravitational waveform analysis, challenging a standard paradigm in numerical relativity.

Contribution

It introduces a new approach to simulate black hole formation without excision, improving stability and waveform calculation in numerical relativity.

Findings

Extended gravitational waveform data beyond previous limits

Stable long-term simulations without singularity excision

Insights into black-hole ringing and gravitational-wave emission

Abstract

A paradigm deeply rooted in modern numerical relativity calculations prescribes the removal of those regions of the computational domain where a physical singularity may develop. We here challenge this paradigm by performing three-dimensional simulations of the collapse of uniformly rotating stars to black holes without excision. We show that this choice, combined with suitable gauge conditions and the use of minute numerical dissipation, improves dramatically the long-term stability of the evolutions. In turn, this allows for the calculation of the waveforms well beyond what previously possible, providing information on the black-hole ringing and setting a new mark on the present knowledge of the gravitational-wave emission from the stellar collapse to a rotating black hole.