In  Menanteau et al., "Southern Cosmology Survey. I. Optical Cluster Detections and Predictions for the Southern Common-Area Millimeter-Wave Experiments", we presented first results from the Southern Cosmology Survey, a new multiwavelength survey of the southern sky coordinated with the Atacama Cosmology Telescope (ACT), a recently commissioned ground-based millimeter (mm)-band cosmic microwave background (CMB) experiment. This article presents full analysis of archival optical multiband imaging data covering an 8 deg2 region near right ascension 23 hr and declination –55°, obtained by the Blanco 4 m telescope and Mosaic-II camera in late 2005. We describe the pipeline we have developed to process this large data volume, obtain accurate photometric redshifts, and detect optical clusters. Our cluster finding process uses the combination of a matched spatial filter, photometric redshift probability distributions, and richness estimation. We present photometric redshifts, richness estimates, luminosities, and masses for eight new optically selected clusters with mass greater than 3 x 1014  Mo at redshifts out to 0.7. We also present estimates for the expected Sunyaev-Zel'dovich effect (SZE) signal from these clusters as specific predictions for upcoming observations by ACT, the South Pole Telescope and Atacama Pathfinder Experiment.

In McInnes et al., we presented the first lensing mass measurements of Sunyaev-Zel'dovich (SZ) selected clusters. Using optical imaging from the Southern Cosmology Survey (SCS), we present weak lensing masses for three clusters selected by their SZ emission in the South Pole Telescope survey (SPT). We confirm that the SZ selection procedure is successful in detecting mass concentrations. We also study the weak lensing signals from 38 optically-selected clusters in ~8 square degrees of the SCS survey. We fit Navarro, Frenk and White (NFW) profiles and find that the SZ clusters have amongst the largest masses, as high as 5 x 1014  Mo Using the best fit masses for all the clusters, we analytically calculate the expected SZ integrated Y parameter, which we find to be consistent with the SPT observations.

In Menanteau and Hughes,  we present the optical and X-ray properties of four clusters recently discovered by the South Pole Telescope (SPT) using the Sunyaev-Zel'dovich effect (SZE). The four clusters are located in one of the common survey areas of the southern sky that is also being targeted by the Atacama Cosmology Telescope (ACT) and imaged by the CTIO Blanco 4 m telescope. Based on publicly available griz optical images and XMM-Newton and ROSAT X-ray observations, we analyze the physical properties of these clusters and obtain photometric redshifts, luminosities, richness, and mass estimates. Each cluster contains a central elliptical whose luminosity is consistent with SDSS cluster studies. Our mass estimates are well above the nominal detection limit of the SPT and ACT; the new SZE clusters are very likely massive systems with 5 x 1014  Mo