Reconstruction of weak lensing mass maps for non-Gaussian studies in the celestial sphere

We present a novel method for reconstructing weak lensing mass or convergence maps as probe to study non-Gaussianities in the cosmic density field. While previous surveys have relied on flat-sky approximation, forthcoming Stage IV will cover such large areas with field of view (FOV) motivate reconstruction sphere. Here, we an improved Kaiser-Squires (KS+) inversion using HEALPix pixelisation sphere while controlling systematic effects. As KS+ methodology, were reconstructed without noise regularisation preserve information content and allow non-Gaussian studies. The results this new compared those (KS) estimator implemented curved sky high-resolution realistic N-body simulations. quality was evaluated by estimating two-point correlation functions, third- fourth-order moments, peak counts maps. effects masking, sampling, tested. also examined errors introduced approximation. show that (SKS+) systematically improves inferred ∼10 times provides average 20–30 % better maximum signal-to-noise estimation (SKS). SKS+ is nearly unbiased reduces factor about 2 4 respectively. Finally, how directly celestial eliminates projection allows exclusion consideration specific region processing.