Large mass-ratio binary mergers with Dendro-GR

Very few binary black hole merger waveforms for large mass ratios (e.g.: q>16), exist with sufficient accuracy for gravitational wave analysis. Binaries with both large mass ratios and spin compound the computational cost, making their waveforms even more rare. Semi-analytic and phenomenological models used for gravitational wave analysis need these waveforms for validating and calibrating their results. Next generation observatories like Cosmic Explorer and LISA will be sensitive to not only a larger range of sources but will also have even higher accuracy requirements—orders of magnitude higher than most present-day simulations. 

The Dendro-GR octree code efficiently simulates such large mass ratio binaries. We present results for binary black hole binaries with q=24 and q=32, as well as other high mass ratios with spin. We discuss computational methods, run efficiency & scaling, refinement methods, the impact of slow-start lapse (SSL) modifications at high mass ratios, and more.