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School of Physics and Astronomy

Cosmology Seminar - José Fonseca (QMUL)

14 October 2020

Time: 3:30 - 5:00pm
Speaker: José Fonseca (QMUL)

Probing the Universe with Radio-Optical Synergies

Next-generation cosmological surveys will probe ever larger volumes of the Universe, including the largest scales, near and beyond the horizon, as well as in different parts of the spectrum. On these scales, signatures of local primordial non-Gaussianity (PNG) and horizon-scale General Relativistic (GR) effects can be found in the power spectrum. However, cosmic variance limits their detection but combining different surveys via the multi-tracer (MT) method allows us to beat down cosmic variance. We will start by revising initial conditions from inflation as well as what we mean by GR effects in the observed power spectrum. We will then explore the concepts behind IM and the MT technique. We follow by presenting forecasts for combinations of contemporaneous surveys that can provide unprecedented constraints on PNG, potentially achieving σ(fNL) below 1, as well as a detection of the GR effects with high accuracy. We will discuss the technical challenges about the implementation of the multi-tracer technique and how to deal with them. We will briefly look at other ways of probing primordial non-Gaussianity. We will finishing with an exploration of other tracers of dark matter and their potentialities.