The millimeter sky as seen with BOOMERanG

BOOMERanG is a balloon-borne, mm-wave scanning telescope, which measured the first images of the CMB with sub-horizon resolution in 1998. In 2003 the instrument has been flown again with polarization sensitive bolometers, and has produced maps of the Stokes parameters I, Q, U of the microwave sky. Three regions of the southern sky were surveyed: a deep (∼90 square degrees) and a shallow survey (∼750 square degrees) at high Galactic latitudes, and a survey of ∼300 square degrees across a southern section of the Galactic plane. The experiment measured simultaneously three wide frequency bands centered at 145, 245 and 345 GHz, with an angular resolution of ∼10′. The 145 GHz temperature maps are dominated by Cosmic Microwave Background (CMB) anisotropy, which is mapped with high signal to noise ratio. The map is consistent with the pattern measured in the same region by BOOMERanG-98 and by WMAP. At 145 GHz, in the high latitude surveys, the intensity and polarization of the astrophysical foregrounds are found to be negligible with respect to the cosmological signal. At 245 and 345 GHz we detect ISD emission correlated to the 3000 GHz IRAS/DIRBE maps. The Q and U maps at high latitudes are dominated by detector noise: a power spectrum analysis allows us to extract from the maps a significant CMB polarization signal.