Morphological Characterization of CMB and Galactic Foreground Emissions

Galactic emissions present significant challenges to the potential detection of CMB signals, such as inflationary B-modes and primordial non-Gaussianity. These foreground emissions include Galactic synchrotron, free-free, thermal dust emissions etc. Accurate modeling of foregrounds is, therefore, essential for effective component separation in CMB experiments. To this end, we investigated the non-Gaussianity and statistical isotropy of foreground emissions using morphological statistics like the Minkowski functionals (MFs) and tensors (MTs). Our analysis of the all-sky Haslam synchrotron map shows that at smaller angular scales, Galactic synchrotron tends to have lesser non-Gaussianity. Importantly, the nature of non-Gaussianity is of kurtosis-type at these scales. Other foreground signals also show varying levels of kurtosis non-Gaussianity, regardless of their different emission mechanisms. These findings highlight the universal nature of ISM fields, having significant implications for modeling foregrounds at small scales. Finally, we studied the morphology of a processed CMB map as a composite field of true signal and noise/residual foregrounds, quantifying the impact of such secondary fields on the primordial non-Gaussianity estimates from CMB.