2008ApJ...673L..13F

We present the first clustering results of X-ray-selected active galactic nuclei (AGNs) at z∼3. Using Chandra X-ray imaging and UVR optical colors from MUSYC photometry in the Extended Chandra Deep Field-South field, we selected a sample of 58 z∼3 AGN candidates. From the optical data we also selected 1385 luminous blue galaxies (LBGs) at 2.8 <z< 3.8 with R<25.5. We performed autocorrelation and cross-correlation analyses, and here we present results for the clustering amplitudes and dark matter (DM) halo masses of each sample. For the LBGs we find a correlation length of r_0,LBG=6.7±0.5 Mpc, implying a bias value of 3.5±0.3 and 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 AGNs 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 DM halos in the ΛCDM cosmology implies that today these z∼3 AGNs are found in high-mass galaxies with a typical luminosity of 7⁺⁴_–2L^*.