X-ray counts of active galactic nuclei in the EMSS sample

Abstract

We have used the largest available AGN sample—the Extended Medium Sensitivity Survey (EMSS) to derive the relation between counts in the energy range 0.3–3.5 keV and flux over the range 1× 10 −11–5 × 10 −14 erg cm −2 s −1. The log N(> S) ∼ log S relation is found to be linear with a gradient of α = − 1.59 ± 0.06. We further calculate the contribution by AGN flux below 5 × 10 −14 erg cm −2 s −1 to the X-rays to be 13.5%.