  Gravitational wave signals from compact astrophysical sources such as those
observed by LIGO and Virgo require a high-accuracy, theory-based waveform model
for the analysis of the recorded signal. Current inspiral-merger-ringdown
models are calibrated only up to moderate mass ratios, thereby limiting their
applicability to signals from high-mass ratio binary systems. We present
EMRISur1dq1e4, a reduced-order surrogate model for gravitational waveforms of
13,500M in duration and including several harmonic modes for non-spinning black
hole binary systems with mass-ratios varying from 3 to 10,000 thus vastly
expanding the parameter range beyond the current models. This surrogate model
is trained on waveform data generated by point-particle black hole perturbation
theory (ppBHPT) both for large mass-ratio and comparable mass-ratio binaries.
We observe that the gravitational waveforms generated through a simple
application of ppBHPT to the comparable mass-ratio cases agree remarkably (and
surprisingly) well with those from full numerical relativity after a rescaling
of the ppBHPT's total mass parameter. This observation and the EMRISur1dq1e4
surrogate model will enable data analysis studies in the high-mass ratio
regime, including potential intermediate mass-ratio signals from LIGO/Virgo and
extreme-mass ratio events of interest to the future space-based observatory
LISA.
