Coping with spurious radiation in binary black hole simulations

Spurious radiation in the initial data for binary black hole numerical simulations has been an issue of concern. The radiation affects the masses and spins of the black holes, modifying their orbital dynamics and thus potentially compromising the accuracy of templates used in gravitational wave analysis. Our study finds that spurious radiation effects are localized to the vicinity of the black holes. Using insights from single black hole simulations, we obtain fitting formulas to estimate the changes from spurious radiation on the mass and spin magnitude of the black holes in binary systems. We demonstrate how these fitting formulas could be used to adjust the initial masses and spin magnitudes of the black holes, so the resulting binary has the desired parameters after the spurious radiation has left the computational domain. A comparison of waveforms from raw simulations with those from simulations that have been adjusted for spurious radiation demonstrate that spurious radiation could have an appreciable effect on the templates for LIGO sources with SNRs above 30.