Distribution of galaxies in the BCS 5 hr field with i < 22.5.
The Blanco Cosmology Survey (BCS) is a 60 night imaging survey of ~80 deg2 of the southern sky located in two fields: (α, δ) = (5 hr, -55°) and (23 hr, -55°). The survey was carried out between 2005 and 2008 in grizbands with the Mosaic2 imager on the CTIO Blanco 4-m telescope. The primary aim of the BCS survey is to provide the data required to optically confirm and measure photometric redshifts for Sunyaev-Zel'dovich effect selected galaxy clusters from the South Pole Telescope and the Atacama Cosmology Telescope. The median 10σ galaxy (point-source) depths over the survey in grizare 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 ~45 mas. Absolute photometry is calibrated using the stellar locus in grizJbands; the absolute photometric scale has ~2% accuracy. The scatter of stars about the stellar locus indicates a systematic floor in the relative stellar photometric scatter in grizthat is ~1.9%, ~2.2%, ~2.7%, and ~2.7%, respectively.
BCS at a Glance
|Years of Observation||2005-2008|
|Sample:||Image mosaics of two survey areas, covering ~45 deg2 at (α, δ) = (5 hr, -55°) and ~35 deg2 at (α, δ) = (23 hr, -55°)|
|Bands||g, r, i, z|
|Median Depth (10σ)||(g, r, i, z) = (23.9, 24.0, 23.6, 22.1)|
|Median Seeing||(g, r, i, z) = (1.1, 1,0, 1.0, and 1.0) arcsec|
|Number of images||928|