The number density of intermediate- and high-luminosity active galactic nuclei at z ∼ 2-3

We use the combination of the 2 Ms Chandra X-ray image, new J and H band images, and the Spitzer IRAC and MIPS images of the Chandra Deep Field-North to obtain high spectroscopic and photometric redshift completeness of high and intermediate X-ray luminosity sources in the redshift interval z = 2-3. We measure the number densities of z 2 3 active galactic nuclei (AGNs) and broad-line AGNs in the rest-frame 2-8 keV luminosity intervals 10(44)-10(45) and 10(43)-10(44) ergs s(-1) and compare these with previous lower redshift results. We confirm a decline in the number densities of intermediate-luminosity sources at z > 1. We also measure the number density of z 2 3 AGNs in the luminosity interval 10(43)-10(44.5) ergs s(-1) and compare it with previous low- and high-redshift results. Again, we find a decline in the number densities at z > 1. In both cases, we can rule out the hypothesis that the number densities remain flat to z 2 3 at above the 5 sigma level.