In this thesis I describe a statistically robust multi-wavelength study on 21 X-ray luminous cluster cores at 
0.15<z<0.3, spanning X-ray to near Infra-Red (NIR) wavelengths, and using weak lens analysis of SNAPSHOT data from the Hubble Space Telescope Advanced Camera for Surveys. Substructures found in the "non-parametric" lensing mass maps are compared with K-band luminosity and Chandra X-ray flux maps. I construct parameterised mass models using a Bayesian statistics based method. Mass-observable scaling relations are used to explore segregation in cluster properties between cool core and non cool core clusters.


The spatial mass distribution is better constrained than the weak lens mass, which suffers a low mass bias due to smoothing systematics. Assuming a constant bias for a constant smoothing scale, the K-band luminosity  scales with mass similarly to the X-ray luminosity.  I also demonstrate the detection of the  weak lens signal of a galaxy group outside the HST:ACS field of view (A3192). I conclude that the analysis algorithm in this thesis could be useful in the analysis of cluster observations from future surveys such as PANSTARRS and DES.