We perform a sequence of binary black hole simulations with increasingly small mass ratios, reaching to a $128:1$ binary that displays 13 orbits before merger. Based on a detailed convergence study of the $q=m_1/m_2=1/15$ nonspinning case, we apply additional mesh refinement levels around the smaller hole horizon [30] to reach successively the $q=1/32$, $q=1/64$, and $q=1/128$ cases. Roughly a linear computational resources scaling with $1/q$ is observed on eight-nodes simulations. We compute the remnant properties of the merger: final mass, spin, and recoil velocity, finding precise consistency between horizon and radiation measures. We also compute the gravitational waveforms: their peak frequency, amplitude, and luminosity. We compare those values with predictions of the corresponding phenomenological formulas, reproducing the particle limit within 2%, and we then use the new results to improve their fitting coefficients.

• Received 8 June 2020
• Revised 30 July 2020
• Accepted 11 September 2020

DOI:https://doi.org/10.1103/PhysRevLett.125.191102