Cluster–galaxy weak lensing

AbstractWeak gravitational lensing of background galaxies provides a direct probe of the projected matter distribution in and around galaxy clusters. Here, we present a self-contained pedagogical review of cluster–galaxy weak lensing, covering a range of topics relevant to its cosmological and astrophysical applications. We begin by reviewing the theoretical foundations of gravitational lensing from first principles, with a special attention to the basics and advanced techniques of weak gravitational lensing. We summarize and discuss key findings from recent cluster–galaxy weak-lensing studies on both observational and theoretical grounds, with a focus on cluster mass profiles, the concentration–mass relation, the splashback radius, and implications from extensive mass-calibration efforts for cluster cosmology.