Detecting gravitational waves from precessing binaries of spinning compact objects. II. Search implementation for low-mass binaries

Abstract

Detection template families (DTFs) are built to capture the essential features of true gravitational waveforms using a small set of phenomenological waveform parameters. Buonanno, Chen, and Vallisneri [Phys. Rev. D 67, 104025 (2003)] proposed the BCV2 DTF to perform computationally efficient searches for signals from precessing binaries of compact stellar objects. Here we test the signal-matching performance of the BCV2 DTF for asymmetric-mass-ratio binaries, and specifically for double-black-hole binaries with component masses $({m}_{1},{m}_{2})\ensuremath{\in}[6,12]{M}_{\ensuremath{\bigodot}}\ifmmode\times\else\texttimes\fi{}[1,3]{M}_{\ensuremath{\bigodot}}$, and for black-hole--neutron-star binaries with component masses $({m}_{1},{m}_{2})=(10{M}_{\ensuremath{\bigodot}},1.4{M}_{\ensuremath{\bigodot}})$; we take all black holes to be maximally spinning. We find a satisfactory signal-matching performance, with fitting factors averaging between 0.94 and 0.98. We also scope out the region of BCV2 parameters needed for a template-based search, we evaluate the template match metric, we discuss a template-placement strategy, and we estimate the number of templates needed for searches at the LIGO design sensitivity. In addition, after gaining more insight in the dynamics of spin-orbit precession, we propose a modification of the BCV2 DTF that is parametrized by physical (rather than phenomenological) parameters. We test this modified ``BCV2P'' DTF for the ($10{M}_{\ensuremath{\bigodot}}$, $1.4{M}_{\ensuremath{\bigodot}}$) black-hole--neutron-star system, finding a signal-matching performance comparable to the BCV2 DTF, and a reliable parameter-estimation capability for target-binary quantities such as the chirp mass and the opening angle (the angle between the black-hole spin and the orbital angular momentum).