Galaxy star formation as a function of environment

We study the galaxy star formation rate (SFR) as a function of environment using the SDSS EDR data. We find that the SFR is depressed in dense environments (clusters and groups) compared to the field. We find that the suppression of the SFR starts to be noticeable at around 4 virial radii. We find no evidence for SF triggering as galaxies fall into the clusters. We also present a project to study these effects in cluster pairs systems where the effects of filaments and large scale structure may be noticeable.