Exploring Statistical Isotropy of the CMB Sky:Real-Space Analysis

Dipanshu Garg

dipanshu@rrimail.rri.res.in

Observations of the cosmic microwave background (CMB) anisotropies have played a key role in developing modern cosmology. Detailed and accurate measurements of the CMB anisotropies tell us a lot about the global properties, the constituents, and the history of the universe. However, WMAP and Planck observations have detected deviations indicating the breakdown of SI. In this talk, I will discuss statistical measures to study deviations from SI. We will discuss the Bipolar Spherical Harmonic (BipoSH) representation of the general covariance structure on the sphere and reduction of the basis to a new irreducible representation leading to a new metric termed mBipoSH functions, depicting real-space angular correlation functions for SI-violated CMB sky. Utilizing this novel basis, we aim to quantify various established sources of SI violation, including Doppler boost, Cosmic Hemispherical Asymmetry (CHA), and systematic effects such as non-circular beam effects. Our analysis showcases promising outcomes in the assessment of these effects, offering a novel mathematical tool for real-space estimations from upcoming ground-based missions.