The 420 square degree observing area and 8» resolution provide sensitivity to an angular power spectrum from 0.2 deg to 5 deg. (physics.columbia.edu)
You have asked the same question I did: WahlAmman2007 criticise MM2005 for using a particular power spectrum for the simulation but do not appear to offer an alternative. (realclimate.org)
The angular power spectrum of polarized dust emission at intermediate and high galactic latitudes. (sciencenews.org)