DR. TUHIN GHOSH

Many CMB experiments are currently searching for the B-mode signal, which has a imprint primordial gravitational waves. The CMB B-mode, if detected, provides the ultimate proof of the existence of the phase of the inflation occurred during the first moments of the Universe. In March 2014, BICEP2 published their results and attributed the measured signal to the CMB B-modes. The main question still remains is “What is the amplitude of B-mode from the polarization of the Galactic dust emission, which hides the background emission?”. Indeed the interstellar dust grains with asymmetric shape and aligned with the magnetic field lines of the Galaxy can produce a significant polarized emission at the CMB frequencies. Thanks to the unprecedented sensitivity of Planck and its wide range of frequency coverage, we are now to able to map the dust B-modes over the full sky. The speaker will present the first results on the dust B-modes that we recently published (http://arxiv.org/abs/1409.5738). He will show the general properties of the dust B-modes and how it is relevant for the BICEP2 like experiments. Finally, he will present the level of dust that we directly measure in the BICEP2 field and invalidating the early assessment of BICEP2 that it is entirely cosmological.