Mass and light in the supercluster of galaxies MS0302+17

We investigate the supercluster MS0302+17 (zapproximate to0.42) using weak lensing analysis and deep wide field BVR photometry with the CFH12K camera. Using (B-V) vs. (V-R) evolution tracks we identify early-type members of the supercluster, and foreground ellipticals. We derive a R band catalogue of background galaxies for weak lensing analysis. We compute the correlation functions of light and mass and their cross-correlation and test if light traces mass on supercluster, cluster and galaxy scales. We show that the data are consistent with this assertion. The zeta-statistic applied in regions close to cluster centers and global correlation analyses over the whole field converge toward the simple relation M/L=300+/-30 h(70) (M/L)(circle dot) in the B band. This independently confirms the earlier results obtained by Kaiser et al. (1998). If we model dark matter halos around each early-type galaxy by a truncated isothermal sphere, we find that a linear relation M proportional to L still holds. In this case, the average halo truncation radius is s(*) less than or similar to200 h(70)(-1) kpc close to clusters cores whereas it reaches a lower limit of similar to300 h(70)(-1) kpc at the periphery. This change of s(*) as a function of radial distance may be interpreted as a result of tidal stripping of early type galaxies. Nevertheless the lack of information on the spatial distribution of late-type galaxies affects such conclusions concerning variations of s(*). Though all the data at hand are clearly consistent with the assumption that mass is faithfully traced by light from early-type galaxies, we are not able to describe in detail the contribution of late type galaxies. We however found it to be small. Forthcoming wide surveys in UV, visible, and near infrared wavelengths will provide large enough samples to extend this analysis to late-type galaxies using photometric redshifts.