Ramanujan Auditorium

Validating the Cosmological principle

Prof. Tarun Souradeep

Raman Research Institute

The Cosmological Principle, a fundamental tenet of the 'standard model of cosmology', predicates a statistically isotropic distribution of fluctuations in the measured Cosmic Microwave Background (CMB) temperature and polarisation sky maps. Enigmatic anomalies claimed in the WMAP and Planck CMB sky maps, and some other recent observations could challenge the standard model. However, these claims need to be cast in an objective mathematical framework and established with statistical rigour. Bayesian inference of the underlying covariance structure of random fields on the sphere in the Bipolar Spherical Harmonic (BipoSH) representation developed in our research program provides such a framework. We review the recent inferences drawn from Planck data and dwell on the future prospects with proposed CMB observations.