AbstractsAstronomy & Space Science

The study and characterization of the Cosmic Microwave Background (CMB) polarized signal represent, nowadays, one of the most im- portant branches of observational cosmology. In the curl component of the CMB polarization (also known as “B-modes”) it is thought to be hiding the imprint of primordial gravitational waves generated during the inflationary epoch. The observation of this signal would therefore open the door to the study of the physics of the very early universe. The CMB B-modes signal is extremely faint, at the level of fraction of µK, and sophisticated experiments with high sensitivity are needed to detect it. Moreover, the control of instrumental systematic effects and the characterization of foreground emission represent important challenges for this kind of measurements. In this thesis we investigated these two issues focusing on two specific and explicatory experimental cases. By analyzing the multi-frequency polarized observations of the Planck satellite, we studied the contamination arising from the Galactic foreground emission in the CMB observation carried out by the BICEP2 experiment. We showed how the polarized thermal dust emission dominates over the CMB B-modes signal at frequencies as low as 150 GHz and even at high Galactic latitudes. For what concern the instrumental systematic effects we developed a simulation pipeline for the LSPE (Large Scale Polarization Explorer) low frequency instrument. LSPE is a future balloon-borne experiment, aimed at observing the CMB polarized signal on the very large angular scales. Our pipeline simulates the sky observation of the STRIP instrument allowing to understand the expected scientific performance. The presence of possible sources of instrumental systematic effects is also considered and their expected impact on final scientific results is determined. Advisors/Committee Members: supervisore: A. Mennella, coordinatore: M. Bersanelli, MENNELLA, ANIELLO, BERSANELLI, MARCO RINALDO FEDELE.