Methods for the detection of gravitational waves from subsolar mass ultracompact binaries

We describe detection methods for extensions of gravitational wave searches to subsolar mass ultracompact binaries. Subsolar mass searches were previously carried out during the Initial LIGO era, and Advanced LIGO boasts a detection volume approximately 1000 times larger than Initial LIGO at design sensitivity. Low mass compact binary searches present computational challenges, and we suggest a way to mitigate the increased computational cost while retaining a sensitivity much greater than previous searches. Subsolar mass compact objects are of particular interest because they are not expected to form astrophysically. If detected, they could be evidence of primordial black holes or some other yet unknown formation mechanism. We consider a particular model of primordial black hole binary formation that would allow LIGO/Virgo to place constraints on this population within the context of dark matter, and we demonstrate how to obtain conservative bounds for the upper limit on the dark matter fraction.