The coalescence of a stellar-mass compact object into an intermediate-mass black hole ( intermediate mass-ratio coalescence ; IMRAC ) is an important astrophysical source for ground-based gravitational-wave interferometers in the so-called advanced ( or second-generation ) configuration .
However , the ability to carry out effective matched-filter based searches for these systems is limited by the lack of reliable waveforms .
Here we consider binaries in which the intermediate-mass black hole has mass in the range 24 \smass - 200 \smass with a stellar-mass companion having masses in the range 1.4 \smass - 18.5 \smass .
In addition , we constrain the mass ratios , q , of the binaries to be in the range 1 / 140 \leq q \leq 1 / 10 and we restrict our study to the case of circular binaries with non-spinning components .
We investigate the relative contribution to the signal-to-noise ratio ( SNR ) of the three different phases of the coalescence : inspiral , merger and ringdown .
We show that merger and ringdown contribute to a substantial fraction of the total SNR over a large portion of the mass parameter space , although in a limited portion the SNR is dominated by the inspiral phase .
We further identify three regions in the IMRAC mass-space in which : ( i ) inspiral-only searches could be performed with losses in detection rates L in the range 10 \% \lesssim L \lesssim 27 \% , ( ii ) searches based on inspiral-only templates lead to a loss in detection rates in the range 27 \% \lesssim L \lesssim 50 \% , and ( iii ) templates that include merger and ringdown are essential to prevent losses in detection rates greater than 50 \% .
We investigate the effectiveness with which the inspiral-only portion of the IMRAC waveform space is covered by comparing several existing waveform families in this regime .
We find that different waveform families are only marginally effective at describing one another , as measured by the “ fitting factor ” .
Our results reinforce the importance of extensive numerical relativity simulations of IMRACs to validate and calibrate semi-analytical waveform families and the need for further studies of suitable approximation schemes in this mass range .