Quantifying substructure in Galaxy Clusters with X-ray and Gravitational Lensing Measurements.

Clusters of galaxies are among the richest astrophysical objects. In order to understand the substructure in galaxy clusters we measure the higher order moments of the X-ray temperature distribution and the lensing mass distribution. The lensing mass distribution is reconstructed using Particle Based Lensing. This is a new technique that combines Strong and Weak (S+W) lensing using variable resolution in an optimal fashion. We do a detailed S+W lensing analysis of A1689 and find significant substructure in core of the dark matter distribution compared to a smooth X-ray temperature distribution. This suggests that the outer region of the cluster is fairly relaxed whereas the dark matter halos in the inner cores are still active. This is also supported by the distribution of galaxies in the optical data. Currently we are doing a similar analysis for 20 supermassive clusters in the local universe. This sample of clusters have exsiting X-ray data from Chandra, XMM and ASCA X-ray, strong lensing data from HST and weak lensing data from SUBARU or MMT. We will present preliminary results on the comparison of the lensing mass distributions and the X-ray temperature distributions for this sample.