Clusters and superclusters of galaxies offer the ideal testing ground with which to investigate the effects of environment on galaxy evolution.  With the combination of wide-field weak gravitational lensing studies and multi-band photometric observations, we are able to link distributions of dark and  luminous matter and ask: how do galaxy properties correlate with environment?  Using deep R-band imaging of the Abell 901/902 supercluster field, we apply weak lensing techniques to reveal the dark matter distribution, including three galaxy clusters at z~0.17 and inter-cluster filamentary structure.  Armed also with the photometric redshifts and spectral classifications from the 17-band dataset, we produce a 3D view of the luminous foreground structure and are able to trace galaxy types and properties as a function of their location in the underlying  density field.  We find strong evidence for segregation by type, with the highest density regions populated almost exclusively by galaxies classified as early-types. We also observe a critical surface mass density above which star-formation activity is truncated.

Contact person:  Meghan Gray, ROE

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