📄 Pixellated Posterior Sampling of Point Spread Functions in Astronomical Images

Authors: Connor Stone, Ronan Legin, Alexandre Adam, Nikolay Malkin, Gabriel Missael Barco, Laurence Perreault-Levasseur, Yashar Hezaveh

arXiv: 2511.19594

We present a method for pixellated posterior sampling of the PSF in astronomical images. Rather than estimating a single best-fit PSF, we infer the full posterior distribution over possible PSF profiles, propagating PSF uncertainty into all downstream measurements. This is essential for weak-lensing shape measurements, deconvolution, and any analysis where PSF mischaracterisation is a dominant systematic.