Mapping the gravitational-wave sky with LISA: a Bayesian spherical harmonic approach

The millihertz gravitational-wave frequency band is expected to contain a rich symphony of signals with sources ranging from galactic white dwarf binaries extreme mass ratio inspirals. Many these will not be individually resolvable. Instead, they incoherently add produce stochastic confusion noise whose content governed by the dynamics sources. angular structure power modulated distribution across sky. Measurement this can yield important information about on and extra-galactic scales, their astrophysics evolution over cosmic timescales. Moreover, since part budget LISA, mapping it also essential for studying resolvable signals. In paper, we present Bayesian algorithm probe LISA using spherical harmonic basis. We develop technique based Clebsch-Gordan coefficients mathematically constrain harmonics non-negative distribution, making them optimal expanding amenable inference. demonstrate techniques series simulations analyses, including recovery simulated distributed localized power. apply method map foreground white-dwarfs simplified model distribution.