Abstract: I will present and discuss a method to constrain primordial non-Gaussianity models using radio-galaxies as tracers of halos of different mass and therefore, bias properties. More precisely, i will focus on radio-continuum surveys such as those planed for the Skare Kilometer Array (SKA) in its initial phase. Using simulated redshift distributions together with the expected evolution of bias for different galaxy populations (Star forming galaxies, Starbust galaxies, Radio-Quiet Quasars, FRI and FRII AGN galaxies), a Fisher matrix analysis was performed based on the predicted auto and cross angular power spectra for these galaxy populations. I will show that such multi-tracer technique can improve the information on non-Gaussianity by reducing the impact of cosmic variance on the constraints. The conclusion is that these surveys, even without delivering redshift information, have the potential to constrain non-Gaussianity to an accuracy 2 to 3 times better than the present contrain obtained with Planck CMB data, opening a window to obtain $\sigma_{f_{nl}}~1$ in the future, thus opening a window to probe inflationary physics.
Place: Physics Dept. Meeting Room, 2th floor, IST