The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of $sim$80 deg$^2$ of the southern sky located in two fields: ($alpha$,$delta$)= (5 hr, $-55^{circ}$) and (23 hr, $-55^{circ}$). The survey was carried out between 2005 and 2008 in $griz$
bands with the Mosaic2 imager on the Blanco 4m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zeldovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. We process and calibrate the BCS data, carrying out PSF corrected model fitting photometry for all detected objects. The median 10$sigma$ galaxy (point source) depths over the survey in $griz$ are approximately 23.3 (23.9), 23.4 (24.0), 23.0 (23.6) and 21.3 (22.1), respectively. The astrometric accuracy relative to the USNO-B survey is $sim45$ milli-arcsec. We calibrate our absolute photometry using the stellar locus in $grizJ$ bands, and thus our absolute photometric scale derives from 2MASS which has $sim2$% accuracy. The scatter of stars about the stellar locus indicates a systematics floor in the relative stellar photometric scatter in $griz$ that is $sim$1.9%, $sim$2.2%, $sim$2.7% and$sim$2.7%, respectively. A simple cut in the AstrOmatic star-galaxy classifier {tt spread_model} produces a star sample with good spatial uniformity. We use the resulting photometric catalogs to calibrate photometric redshifts for the survey and demonstrate scatter $delta z/(1+z)=0.054$ with an outlier fraction $eta<5$% to $zsim1$. We highlight some selected science results to date and provide a full description of the released data products.
The South Pole Telescope (SPT) is a 10 meter telescope operating at mm wavelengths. It has recently completed a three-band survey covering 2500 sq. degrees. One of the surveys main goals is to detect galaxy clusters using Sunyaev-Zeldovich effect and
use these clusters for a variety of cosmological and astrophysical studies such as the dark energy equation of state, the primordial non-gaussianity and the evolution of galaxy populations. Since 2005, we have been engaged in a comprehensive optical and near-infrared followup program (at wavelengths between 0.4 and 5 {mu}m) to image high-significance SPT clusters, to measure their photometric redshifts, and to estimate the contamination rate of the candidate lists. These clusters are then used for various cosmological and astrophysical studies.
