Journal Club

Sadra Jazayeri, "Non-Gaussianity and New Probes of Spatial Curvature"

Thursday, November 21, 2019 from to (Europe/Berlin)
at Blg 2a ( 4th floor (Library) )
Description
Cosmological observations have virtually saturated their maximum precision in determining the value of spatial curvatures, and by far CMB and BAO data are consistent with a flat background geometry. Given that direct measurements of Ωk will be unlikely to improve the current bounds in any foreseeable future, it is important to look out for indirect signals sensitive to small values for Ωk. In this work, we inspect the interplay between non-gaussianity and spatial curvature. We first point out that in the presence of equilateral and orthogonal non-gaussianities, the power spectrum receives potentially sizable modifications proportional to Ωk. We study how this new signal can lead to improved constraints on Ωk and non-gaussianity by looking at the measured low-ell multipole moments of CMB TT anisotropies, and we discuss the subtleties present in the perturbative treatment of Ωk. In addition, we compute the modification of the bispectrum up to leading order, and we present the observational bounds on the size of the signal in the squeezed and equilateral shapes of the three-point function.