Targeted large mass ratio numerical relativity surrogate waveform model for GW190814

Abstract

Gravitational wave observations of large mass ratio compact binary mergers like GW190814 highlight the need for reliable, high-accuracy waveform templates for such systems. We present nrhybsur2dq15, a new surrogate model trained on hybridized numerical relativity (NR) waveforms with mass ratios q≤15 and aligned spins |χ1z| ≤ 0.5 and χ2z = 0. We target the parameter space of GW190814-like events as large mass ratio NR simulations are very expensive. The model includes the (2, 2), (2, 1), (3, 3), (4, 4), and (5, 5) spin-weighted spherical harmonic modes and spans the entire LIGO-Virgo bandwidth (with flow = 20 Hz) for total masses M ≳ 9.5  M⊙. nrhybsur2dq15 accurately reproduces the hybrid waveforms, with mismatches below ∼2 × 10⁻³ for total masses 10 M⊙ ≤ M ≤ 300 M⊙. This is at least an order of magnitude improvement over existing semianalytical models for GW190814-like systems. Finally, we reanalyze GW190814 with the new model and obtain source parameter constraints consistent with previous work.

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