Robustness of Binary Black Hole Mergers in the Presence of Spurious Radiation

TL;DR

This study examines how spurious initial radiation affects the dynamics and merger timing of binary black hole systems, revealing that increased spurious energy accelerates mergers and influences orbital eccentricity.

Contribution

It provides the first detailed numerical analysis of the impact of spurious radiation on binary black hole mergers, highlighting the sensitivity of merger timing to initial data contamination.

Findings

Merger is hastened with increased spurious radiation energy.

Significant effects occur when ADM mass increases by about 1%.

Final black hole spins remain unaffected by spurious radiation.

Abstract

We present an investigation into how sensitive the last orbits and merger of binary black hole systems are to the presence of spurious radiation in the initial data. Our numerical experiments consist of a binary black hole system starting the last couple of orbits before merger with additional spurious radiation centered at the origin and fixed initial angular momentum. As the energy in the added spurious radiation increases, the binary is invariably hardened for the cases we tested, i.e. the merger of the two black holes is hastened. The change in merger time becomes significant when the additional energy provided by the spurious radiation increases the Arnowitt-Deser-Misner (ADM) mass of the spacetime by about 1%. While the final masses of the black holes increase due to partial absorption of the radiation, the final spins remain constant to within our numerical accuracy. We conjecture that the spurious radiation is primarily increasing the eccentricity of the orbit and secondarily increasing the mass of the black holes while propagating out to infinity.