Abstract

We present the first clustering results of X-ray selected AGN at z ? 3. Using Chandra X-ray imaging and UVR optical colors from MUSYC photometry in the ECDF-S field, we selected a sample of 58 z ? 3 AGN candidates. From the optical data we also selected 1385 LBG at 2.8 < z < 3.8 with R < 25:5. We performed auto-correlation and cross-correlation analyses, and here we present results for the clustering amplitudes and dark matter halo masses of each sample. For the LBG we find a correlation length of r 0,LBG = 6.7 ± 0.5 Mpc, implying a bias value of 3.5±0.3 and dark matter (DM) halo masses of log(M min/M?) = 11.8 ± 0:1. The AGN-LBG cross-correlation yields r 0,AGN-LBG = 8.7 ± 1.9 Mpc, implying for AGN at 2.8 < z < 3.8 a bias value of 5.5±2.0 and DM halo masses of log(M min/M?) = 12:6 +0:5 0.8. Evolution of dark matter halos in the Lambda CDM cosmology implies that today these z ? 3 AGN are found in high mass galaxies with a typical luminosity 7 +4 -2L*.