DR. NIDHI PANT

The standard model of cosmology is built upon certain fundamental assumptions such as statistical homogeneity and Statistical Isotropy (SI). Comprehensive study of inferences from the data obtained from CMB experiments with high sensitivity and high resolution can shed light on robustness of these assumptions. The anomalies pointing towards breakdown of these fundamental assumptions have been floating around in the data since the release of WMAP’s first year of data (2003) to the era of Planck (2013). These anomalies can be due to some theoretically plausible cosmological model or can be merely a systematic artifact. It is very important to decouple the imprints of these sources on CMB data to make any conclusive statement about the source of breakdown of SI. The subtle SI violation signals coming from systematic effects require an effective mathematical modeling so that they can be removed from data. BipoSH representation of SI violation is an extremely effective way of characterizing, and possibly, isolating the various sources of breakdown of SI in CMB maps. We demonstrate that the subtle SI violation effects coming from non-circular beams and masking are very well captured in BipoSH formalism providing a way to tackle systematic effects in data.