HET-Discovery seminar by Pankaj Jain – University of Copenhagen

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HET-Discovery seminar by Pankaj Jain

Title: Large Scale Anisotropy in the Universe

Abstract: There are many indications that the cosmological principle might be violated. I will review these observations and the theoretical attempts to explain them. The most prominent effects are the observed dipole anisotropies in radio source distribution, brightness, polarized flux and polarization orientations. All of these suggest a preferred direction pointing roughly towards the Virgo supercluster. The direction also approximately agrees with the CMBR dipole and, surprisingly, the CMBR quadrupole and octopole also point roughly in this direction. Another interesting effect is the hemispherical anisotropy seen in CMBR. Theoretically these anisotropies might arise due to modes generated during the very early phase of inflation when the Universe might not obey the principle of isotropy and homogeneity. I will describe our fits to the CMBR data based on this idea. This model will be tested in future CMBR polarization data as well as in radio surveys, such as Square KM Array. An interesting aspect of this model is that it predicts a difference between the CMB TE and ET correlations due to the inhomogeneous and/or anisotropic contributions.