The clustering of galaxies around three z ∼ 3 damped Lyα absorbers

We present our results on the cross-correlation of Lyman break galaxies (LBGs) around three damped Lyalpha absorbers (DLAs) at z(abs) similar or equal to 3 from deep [mu(I, AB)(sky) similar or equal to 27.6 mag arcsec(-2)] UBVI KPNO 4 m/MOSAIC images. The large area of the MOSAIC images, 0.31 deg(2) or similar to65 x 65 h(71)(-1) Mpc comoving at redshift z = 3, allows us to probe the clustering of LBGs on scales up to 20 Mpc comoving. Our survey covers a total of 1 deg2 and contains similar to3000 LBGs with photometric redshifts between 2.8 and 3.5. Using the redshift likelihood distributions with mI as a prior, we selected LBGs within a redshift slice of width W-z = 0.15 (corresponding to sigma(z), the uncertainty in photometric redshifts) centered on the redshift of the absorbers. Within that redshift slice, we find that the DLA-LBG cross-correlation w(dg) is w(dg) = (1.62 +/- 1.32) x w(gg) where w(gg) is the LBG autocorrelation. This corresponds to a correlation length of r(0) = 5 +/- 4.5 h(-1) (comoving) (or r(0) = 7 +/- 6.8 h(71)(-1) Mpc). The cross-correlation is most significant on scales 5-10 Mpc. Through Monte Carlo simulations, we find that wdg is significantly greater than zero at the greater than 95% level. In three other redshift slices that do not contain a DLA, we do not find any evidence of clustering. A larger sample will enable us to discriminate between w(dg)/w(gg) < 1 and w(dg)/w(gg) > 1, i.e., to test whether DLA halos are more or less massive than LBG halos.