Detecting a Stochastic Gravitational Wave Background in the presence of a Galactic Foreground and Instrument Noise

Department of Physics, Montana State University, Bozeman, MT 59717(Dated: January 10, 2014)Detecting a stochastic gravitational wave background requires that we rst understand and modelany astrophysical foregrounds. In the millihertz frequency band, the predominate foreground signalwill be from unresolved white dwarf binaries in the galaxy. We build on our previous work to showthat a stochastic gravitational wave background can be detected in the presence of both instrumentnoise and a galactic confusion foreground. The key to our approach is accurately modeling thespectra for each of the various signal components. We simulate data for a gigameter Laser Interfer-ometer Space Antenna (LISA) operating in the mHz frequency band detector operating with both6- and 4-links. We obtain posterior distribution functions for the instrument noise parameters, thegalaxy level and modulation parameters, and the stochastic background energy density. We ndthat we are able to detect a scale-invariant stochastic background with energy density as low as