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P. Gomez (Carnegie Mellon Univesity), R. Nichol, C. Miller, T. Goto (Univ. of Tokio/CMU)
We present an analysis of the star formation rate of nearby galaxies (i.e., 0.05< z <0.09) as a function of the environment. We concentrate on two environmental parameters: the local galaxy density and the cluster center distance for a subsample of cluster galaxies. Our analysis is based on the Early Data Release of the Sloan Digital Sky Survey spectroscopic survey of the Northern Galactic Hemisphere which has allowed us to use over 20000 galaxy spectra. We find that, on average, the star formation rate in a galaxy steadly decreases towards the cluster center. This behaviour is similar to what has already been found in mid z clusters. In addition, we also find that the star formation rate decreases in high galaxy density environments with respect to low density environments. We propose that this star formation density relation is similar to the well know morphology-density relation. This suggests that the main mechanism responsible for the decline of star formation within clusters is the ram pressure stripping of the star forming gas.