Black hole head-on collisions and gravitational waves with fixed mesh-refinement and dynamic singularity excision

TL;DR

This paper demonstrates stable long-term simulations of head-on black hole collisions using fixed mesh-refinement and dynamic singularity excision, successfully capturing gravitational wave emission and black hole merger dynamics.

Contribution

Introduces fixed mesh-refinement and dynamic excision techniques enabling long-term stable head-on black hole collision simulations with accurate gravitational wave extraction.

Findings

Successfully simulated large initial separations of black holes.

Extracted gravitational waves dominated by the l=2, m=0 mode.

Total radiated energy about 0.1% of system mass.

Abstract

We present long-term-stable and convergent evolutions of head-on black hole collisions and extraction of gravitational waves generated during the merger and subsequent ring-down. The new ingredients in this work are the use of fixed mesh-refinement and dynamical singularity excision techniques. We are able to carry out head-on collisions with large initial separations and demonstrate that our excision infrastructure is capable of accommodating the motion of the individual black holes across the computational domain as well as their their merger. We extract gravitational waves from these simulations using the Zerilli-Moncrief formalism and find the ring-down radiation to be, as expected, dominated by the l=2, m=0 quasi-normal mode. The total radiated energy is about 0.1 % of the total ADM mass of the system.