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We study the star formation rates (SFRs) of galaxies as a function of localgalaxy density at 0.6<z<0.9. We used a low-dispersion prism in IMACS on the6.5-m Baade (Magellan I) telescope to obtain spectra and measured redshifts toa precision of sigma_z/(1+z)=1% for galaxies with z<23.3 AB mag. We utilized astellar mass-limited sample of 977 galaxies above M>1.8x10^{10} Msun to conductour main analysis. With three different SFR indicators, (1) Spitzer MIPS24-micron imaging, (2) SED fitting, and (3) [OII]3727 emission, we find themedian specific SFR (SSFR) and SFR to decline from the low-density field to thecores of groups and a rich cluster. For the SED and [OII] based SFRs, thedecline in SSFR is roughly an order of magnitude while for the MIPS based SFRs,the decline is a factor of ~4. We find approximately the same magnitude ofdecline in SSFR even after removing the sample of galaxies near the cluster.Galaxies in groups and a cluster at these redshifts therefore have lower starformation (SF) activity than galaxies in the field, as is the case at z~0. Weinvestigated whether the decline in SFR with increasing density is caused by achange in the proportion of quiescent and star forming galaxies (SFGs) or by adecline in the SFRs of SFGs. Using the rest-frame U-V and V-J colors todistinguish quiescent galaxies from SFGs we find the fraction of quiescentgalaxies increases from ~32% to 79% from low to high density. In addition, wefind the SSFRs of SFGs, selected based on U-V and V-J colors, to decline withincreasing density by factors of ~5-6 for the SED and [OII] based SFRs. TheMIPS based SSFRs for SFGs decline with a shallower slope. The order ofmagnitude decline in the SSFR-density relation at 0.6<z<0.9 is therefore drivenby both a combination of declining SFRs of SFGs as well as a changing mix ofSFGs and quiescent galaxies [ABRIDGED].

The Star Formation Rate-Density Relation at 0.6