Description
Weak gravitational lensing by large-scale structures offers a powerful technique for directly mapping the distribution of matter in the Universe. Following this principle, we recently produce the highest-resolution dark matter maps of the 0.54 square degree COSMOS-Web field to date. These maps are derived from weak lensing cosmic shear measurements using the James Webb Space Telescope (JWST) NIRCam, for which our weak lensing source catalogues achieves a density of approximately 150 galaxies per square arcminute.
In this talk, we would like to detail the state of the art methods assembled for the first time to produce these maps and its astrophysical impacts. We would discuss key aspects of weak lensing theory, the enhanced Kaiser-Squires mass inversion (KS+) method and the MRLens filtering approach used to generate the maps while mitigating systematic effects. Then, we apply a fast multiscale algorithm to detect the galaxy clusters of the field based on their weak lensing signal and compare their properties with X-ray and optical clusters. We compare the JWST-derived maps with those from the Hubble Space Telescope (HST) and highlight the locations of new galaxy clusters detected based on their weak lensing signal.
