The NuSTAR Extragalactic Surveys: The Number Counts Of Active Galactic Nuclei And The Resolved Fraction Of The Cosmic X-ray Background

Abstract: We present the 3-8 kiloelectronvolts and 8-24 kiloelectronvolts number counts of active galactic nuclei (AGNs) identified in the Nuclear Spectroscopic Telescope Array (NuSTAR) extragalactic surveys. NuSTAR has now resolved 33 percent -39 percent of the X-ray background in the 8-24 kiloelectronvolts band, directly identifying AGNs with obscuring columns up to approximately 10 (exp 25) per square centimeter. In the softer 3-8 kiloelectronvolts band the number counts are in general agreement wi…