Searching for gravitational waves from the inspiral of precessing binary systems: New hierarchical scheme using “spiky” templates

In a recent investigation of the effects of precession on the anticipated detection of gravitational-wave inspiral signals from compact object binaries with moderate total masses 10M_, we found that (i) if precession is ignored, the inspiral detection rate can decrease by almost a factor of 10, and (ii) previously proposed ``mimic'' templates cannot improve the detection rate significantly (by more than a factor of 2). In this paper we propose a new family of templates that can improve the detection rate by a factor of 5 or 6 in cases where precession is most important. Our proposed method for these new ``mimic'' templates involves a hierarchical scheme of efficient, two-parameter template searches that can account for a sequence of spikes that appear in the residual inspiral phase, after one corrects for any oscillatory modification in the phase. We present our results for two cases of compact object masses (10 and 1. 4M_ and 7 and 3M_) as a function of spin properties. Although further work is needed to fully assess the computational efficiency of this newly proposed template family, we conclude that these ``spiky templates'' are good candidates for a family of precession templates used in realistic searches that can improve detection rates of inspiral events.