Gravitational wave radiometry: Mapping a stochastic gravitational wave background

Understand

The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either of cosmological or astrophysical origin, bears a strong semblance to the analysis of CMB anisotropy and polarization.

• The basic statistic we use is the cross-correlation between the data from a pair of detectors.
• In order to `point' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction.
• Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky.