Measurement of the spatial cross-correlation function of damped Ly alpha systems and Lyman break galaxies

We present the first spectroscopic measurement of the spatial cross-correlation function between damped Ly alpha systems (DLAs) and Lyman break galaxies (LBGs). Analysis of deep u'BVRI imaging of nine QSO fields with 11 known z similar to 3 DLAs has spectroscopically confirmed 211 z > 2 LBGs to R = 25.5. We find strong evidence for an overdensity of LBGs near DLAs versus random, the results of which are similar to that of LBGs near other LBGs. A maximum likelihood cross-correlation analysis finds the best-fit value for the correlation length to be r(0) = 2.9(-1.5)(+1.4) h(-1) Mpc using a fixed value of gamma = 1.6. The implications of the DLA-LBG clustering amplitude on the average dark matter halo mass of DLAs are discussed.