Selection effects in resolving Galactic binaries with LISA

Abstract

Using several realisations of the Galactic population of close white dwarf binaries, we have explored the selection bias for resolved binaries in the LISA data stream. We have assumed a data analysis routine that is capable of identifying binaries that have a signal to noise ratio of at least 5 above a confusion foreground of unresolved binaries. The resolved population of binaries is separated into a subpopulation over 1000 binaries that have a measureable chirp and another subpopulation over 20,000 binaries that do not. As expected, the population of chirping binaries is heavily skewed toward high frequency, high chirp mass systems, with little or no preference for nearby systems. The population of non-chirping binaries is still biased toward frequencies above about 1 mHz. There is an overabundance of higher mass systems than is present in the complete Galactic population.