The OPTX Project II: Hard X-ray Luminosity Functions of Active Galactic Nuclei for z<5

TL;DR

This study constructs and analyzes the hard X-ray luminosity functions of active galactic nuclei up to redshift 5 using extensive Chandra and SWIFT BAT data, providing insights into AGN evolution.

Contribution

It presents the largest uniform sample for HXLFs of AGNs up to z<5 and introduces new model fits, especially the luminosity dependent density evolution model.

Findings

HXLFs constructed up to z~5 for the first time.

The LDDE model best fits the combined data.

Provides a comprehensive view of AGN evolution over cosmic time.

Abstract

We use the largest, most uniform, and most spectroscopically complete to faint X-ray flux limits Chandra sample to date to construct hard 2-8 keV rest-frame X-ray luminosity functions (HXLFs) of spectroscopically identified active galactic nuclei (AGNs) to z~5. In addition, we use a new 2-8 keV local sample selected by the very hard (14-195 keV) SWIFT 9-month Burst Alert Telescope (BAT) survey to construct the local 2-8 keV HXLF. We do maximum likelihood fits of the combined distant plus local sample (as well as of the distant sample alone) over the redshift intervals 0<z<1.2, 0<z<3, and 0<z<5 using a variety of analytic forms, which we compare with the HXLFs. We recommend using our luminosity dependent density evolution (LDDE) model fits of the combined distant plus local sample over 0<z<3 for all the spectroscopically identified sources and for the broad-line AGNs.