Precision CMB Polarization from Dome-C: the BRAIN experiment

¹ Department of Physics, University of Rome “La Sapienza”, Italy
² Department of Physics, University of Milano Bicocca, Italy
³ ISTARS and Agenzia Spaziale Italiana, Italy
⁴ Cosmology Group, Collège de France, Paris, France
⁵ CESR, Toulouse, France
⁶ Department of Physics and Astronomy, University of Cardiff, UK

Abstract

In the current cosmological scenario, part of the linearly polarized emission of the CMB is expected to be rotational (B-modes). This component is due to tensor perturbations of the metric produced by primordial gravitational waves, which are generated a split-second after the Big Bang. The signal expected is of the order of ≲ 0.1 μK, well below the non-rotational component of the polarization signal (E-modes), and beyond the sensitivity of present generation instruments. New, more sensitive instruments are developed in several labs, with the goal to measure the B-modes. Control of systematics and foregrounds will be the key to make the results of these experiments believable. In this paper we shortly outline BRAIN, a bolometric interferometer devoted to B-modes research, and its pathfinder experiment, devoted to test the Dome-C site.