We present the first clustering results of X-ray selected AGN at z \sim 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 \sim 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 \pm 0.5 Mpc , implying a bias value of 3.5 \pm 0.3 and dark matter ( DM ) halo masses of log ( M _ { min } / M _ { \odot } ) = 11.8 \pm 0.1 .
The AGN-LBG cross-correlation yields r _ { 0 ,AGN - LBG } = 8.7 \pm 1.9 Mpc , implying for AGN at 2.8 < z < 3.8 a bias value of 5.5 \pm 2.0 and DM halo masses of log ( M _ { min } / M _ { \odot } ) = 12.6 _ { -0.8 } ^ { +0.5 } .
Evolution of dark matter halos in the Lambda CDM cosmology implies that today these z \sim 3 AGN are found in high mass galaxies with a typical luminosity 7 _ { -2 } ^ { +4 } L ^ { * } .