=========================================================================== COSMOS Sloan Digital Sky Survey (SDSS) Data Version 2.0 =========================================================================== The Cosmic Evolution Survey (COSMOS) is an HST Treasury Project to survey a 2 square degree equatorial field, centered on RA=10:00:28.6 and DEC=+02:12:21.0, using the ACS camera. The project also incorporates major commitments from other observatories around the world, including the VLA radio telescope, ESO's VLT in Chile, ESA's XMM X-ray satellite, and the Japanese 8-meter Subaru telescope in Hawaii. These data are imaging taken as part of the Sloan Digital Sky Survey (SDSS) project. The data were downloaded from the DR2 archive, and calibrated using the best photometry in the tsField files. They were combined into a single image using the COSMOS astrometric frame generated from the VLA data and CFHT i* image. These data are psf homogenized. The filter transmission profiles for each filter are included in the files SDSS_filter_N.txt, where "N" is the filter name. The u' filter has a known red leak, however it is not given in the filter profile provided by SDSS. The PSF homogenization of these SDSS data are not perfect. For a 3" aperture, variations of approximately +/-0.05 mag are observed in the aperture correction as a function of position . The effect is smaller for colors measured between two SDSS bands because the offsets are similar in all bands. The key characteristics of these data are: Telescope: SDSS 2.5m Telescope Instrument: SDSS Camera Data Release: DR2 Integration time: 53.9s Effective Wavelength: 472.3nm (g) 752.3nm (i) 621.3nm (r) 359.1nm (u) 885.5nm (z) Filter Width: 130.0nm (g) 130.0nm (i) 120.0nm (r) 55.0nm (u) 100.0nm (z) Flux unit: nJy Zero Point 31.4 Area: 4 sq degrees Resolution: 0.15"/pix Seeing: 1.97" (g, i, u, z) 1.0-1.7" (r) PSF Homogenized: YES The data products available here include the following at each of 144 tiled positions: 1) an image in units of nJy 2) a map of the image RMS in units of nJy A tile diagram is included with the data. Reduced data were provided by the Sloan Digital Sky Survey Second Data Release (SDSS DR2) http://www.sdss.org/. Images were combined by Peter Capak (capak@astro.caltech.edu) using the IMCAT software package. More information on IMCAT can be found at: http://www.ifa.hawaii.edu/~kaiser/imcat/ This data was prepared for release by: Peter Capak (capak@astro.caltech.edu) Patrick Shopbell (pls@astro.caltech.edu) Further information may be obtained from the COSMOS web page: http://cosmos.astro.caltech.edu/ ===========================================================================