Survey for Galaxies Associated withz∼ 3 Damped Lyα Systems. I. Spectroscopic Calibration ofu′BVRIPhotometric Selection

We present a survey for z~3 Lyman break galaxies (LBGs) associated withdamped Lyman alpha systems (DLAs) with the primary purpose of determining theDLA-LBG cross-correlation. This paper describes the acquisition and analysis ofimaging and spectroscopic data of 9 quasar fields having 11 known z~3 DLAscovering an area of 465 arcmin^2. Using deep u'BVRI images, 796 LBG candidatesto an apparent R_AB magnitude of 25.5 were photometrically selected from 17,343sources detected in the field. Spectroscopic observations of 529 LBG candidatesusing Keck LRIS yielded 339 redshifts. We have conservatively identified 211z>2 objects with =3.02+/-0.32. We discuss our method of z~3 LBGidentification and present a model of the u'BVRI photometric selectionfunction. We use the 339 spectra to evaluate our u'BVRI z~3 Lyman breakphotometric selection technique.Comment: 26 pages, 6 tables, 11 figures, accepted for publication in Ap