  We present the BOOMERanG-03 experiment and maps of the Stokes parameters I,
Q, U of the microwave sky obtained during a 14 day balloon flight in 2003.
Three regions of the southern sky were surveyed: a deep survey (~ 90 square
degrees) and a shallow survey (~ 750 square degrees) at high Galactic latitudes
(both centered at RA ~ 5.5 h, dec ~ -45 deg) and a survey of ~ 300 square
degrees across the Galactic plane at RA ~ 9.1 h, dec ~ -47 deg. All three
surveys were carried out in three wide frequency bands centered at 145, 245 and
345 GHz, with an angular resolution of ~ 10'. The 145 GHz maps of Stokes I are
dominated by Cosmic Microwave Background (CMB) temperature anisotropy, which is
mapped with high signal to noise ratio. The measured anisotropy pattern is
consistent with the pattern measured in the same region by BOOMERanG-98 and by
WMAP. The 145 GHz maps of Stokes Q and U provide a robust statistical detection
of polarization of the CMB when subjected to a power spectrum analysis. This
amplitude of the polarization is consistent with that of the CMB in the
$\Lambda$CDM cosmological scenario. At 145 GHz, in the CMB 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, and give upper
limits for any other non-CMB component. We also present intensity maps of the
surveyed section of the Galactic plane. These are compared to monitors of
different interstellar components, showing that a variety of emission
mechanisms is present in that region.
