The Bright Ages Survey. I. Imaging Data

This is the first paper in a series presenting and analyzing data for aK-selected sample of galaxies collected in order to identify and study galaxiesat moderate to high redshift in rest-wavelength optical light. The samplecontains 842 objects over 6 separate fields covering 75.6 arcmin^2 down toK=20-20.5. We combine the K-band with UBVRIzJH multi-band imaging, reachingdepths of R~26. Two of the fields studied also have deep HST WFPC2 imaging,totaling more than 60 hours in the F300W, F450W, F606W, and F814W filters.Using artificial galaxy modeling and extraction we measure 85% completenesslimits down to K=19.5-20, depending on the field examined. The derived K-bandnumber counts are in good agreement with previous studies. We find a densityfor Extremely Red Objects(EROs; R-K>5) of 1.55+/-0.16 arcmin^{-2} for K<19.7,dominated by the 1714+5015 field (centered on 53w002), with an ERO numberdensity more than 3 times that of the other sample fields. If we exclude thecounts for 1714+5015, our density is 0.95+/- 0.14 arcmin. Both ERO densitiesare consistent with previous measurements due to the significant known cosmicvariance of these red sources.Keck spectroscopic redshifts were obtained for 18of the EROs, all but one of which are emission galaxies. None of the EROs inthe 1714+5015 field for which we obtained spectroscopic redshifts areassociated with the known z=2.39 over-density, although there are threedifferent galaxy redshift pairs (z=0.90, z=1.03, z=1.22).Comment: 30 pages, 5 figures, accepted by Ap