Investigating non-Gaussianity in Cosmic Microwave Background temperature maps using spherical harmonic phases

In this article, we extend previous studies based on CMB spherical harmonic phases (SHP) to examine the validity of hypothesis that temperature field is consistent with a Gaussian random (GRF). The null corresponding SHP are independent and identically distributed in terms uniform distribution interval [0, 2$\pi$] \citep{1986ApJ...304...15B,2013rossmanith}. We devise new model-independent method where use ordered non-parametric Rao's statistic, sample arc-lengths comprehensively test uniformity independence SHP. performed our analysis scales limited by modes $\le$ 128, restrict ourselves signal-dominated regions. To find non-uniform or dependent sets SHP, calculate statistic for data 10000 Monte Carlo simulated uniformly 0.05 0.001 $\alpha$ levels distinguish between statistically significant highly detections. first establish performance using Gaussian, non-Gaussian maps, along observed 100 143 GHz Planck channel maps. performs efficiently accurately detecting phase correlations generated all simulations foreground contaminated apply satellite mission's final released anisotropy maps- COMMANDER, SMICA, NILC, SEVEM WMAP 9 year ILC map. report some $m$-modes non-uniform, $\ell$ mode neighboring pair correlated cleaned detection non-uniformity correlation indicates presence signals minimized