C. Sbarra

The Sky Polarization Observatory

Abstract The Sky Polarization Observatory (SPOrt) is an ASI-funded experiment specifically designed to measure the sky polarization at 22, 32 and 90 GHz, which was selected in 1997 by ESA to be flown on the International Space Station. Starting in 2006 and for at least 18 months, it will be taking direct and simultaneous measurements of the Stokes parameters Q and U at 660 sky pixels, with FWHM=7°. Due to development efforts over the past few years, the design specifications have been significantly improved with respect to the first proposal. Here we present an up-to-date description of the instrument, which now warrants a pixel sensitivity of 1.7 μK for the polarization of the cosmic background radiation, assuming two years of observations. We discuss SPOrt scientific goals in the light of WMAP results, in particular in connection with the emerging double-reionization cosmological scenario.

A polarized synchrotron template for cosmic microwave background polarization experiments based on WMAP data

We build template maps for the polarized Galactic--synchrotron emission on large angular scales (FWHM =~7

A new approach for a Galactic synchrotron polarized emission template in the microwave range

^\circ

The SPOrt experiment

), in the 20-90 GHz microwave range, by using WMAP data. The method, presented in a recent work, requires a synchrotron total intensity survey and the {\it polarization horizon} to model the polarized intensity and a starlight polarization map to model polarization angles. The basic template is obtained directly at 23 GHz with about 94% sky--coverage by using the synchrotron map released by the WMAP team. Extrapolations to 32, 60 and 90 GHz are performed by computing a synchrotron spectral index map, which strongly reduces previous uncertainties in passing from low (1.4 GHz) to microwave frequencies. Differing from low frequency data, none of our templates presents relevant structures out of the Galactic Plane. Our map at 90 GHz suggests that the synchrotron emission at high Galactic latitudes is low enough to allow a robust detection of the

High stability and sensitivity correlation polarimeters for CMB polarization measurements

E

SPOrt: an experiment aimed at measuring the large scale cosmic microwave background polarization

--mode component of the cosmological signal on large--scale, even in models with low--reionization (

BaR-SPOrt experiment

\tau = 0.05

The BaR-SPOrt experiment

). Detection of the weaker

Astrophysical Polarized Backgrounds

B

An iterative destriping technique for diffuse background polarization data

--mode on the largest scales (