Gravitational Waves from Extragalactic Inspiraling Binaries: Selection Effects and Expected Detection Rates

We examine the selection effects that determine how the population ofinspiraling binary compact objects (BCOs) is reflected by those potentiallyobserved with ground-based interferometers like LIGO. We lay the ground-workfor the interpretation of future observations in terms of constraints on thereal population and, correspondingly, binary star evolution models. To determine the extra-galactic population of inspiraling binaries we combinedata on distance and blue luminosity from galaxy catalogs with current modelsof the galactic BCO mass distribution to simulate the physical distribution ofbinaries in the nearby universe. We use Monte Carlo methods to determine thefraction of binaries observable by the LIGO detectors from each galaxy as afunction of the BCO chirp mass. We examine separately the role of sourcedistance, sky position, time of detection, and binary system chirp mass ondetection efficiency and selection effects relevant to the three LIGOdetectors. Finally, we discuss the implications of the nearby geography ofspace on anticipated GW detection and compare our results to previous studies,which have assumed uniform galaxy volume density and fixed chirp mass forbinary compact objects. From these considerations, actual BCO inspiral observations or significantupper limits on the coalescence rate anticipated in the near future byground-based interferometers can be used to improve our knowledge of thegalactic binary inspiral rate and to constrain models of radio pulsarcharacteristics and binary star evolution channels leading to neutron star orblack hole binaries.Comment: 35 pages, including 12 figures. Revised following refereeing. Accepted for September publication in Ap