X-ray Sources in the SSA22 Chandra Field

TL;DR

This study presents new optical spectroscopy and constructs X-ray luminosity functions for AGNs in the SSA22 field, revealing their evolution and the increasing dominance of broad-line AGNs at higher redshifts and luminosities.

Contribution

It provides the first comprehensive XLFs for AGNs in SSA22, combining new and existing data, and distinguishes the evolutionary behaviors of BLAGNs and non-BLAGNs.

Findings

XLFs agree with previous studies, showing strong evolution from z=0.25 to 4.

BLAGNs become more prevalent at higher redshifts and luminosities.

The study enhances understanding of AGN evolution in a deep Chandra field.

Abstract

The Hawaii Survey Field SSA22 is the fourth deepest Chandra X-ray field. To allow for the fullest exploration of this field, we present new optical spectroscopy from Keck/DEIMOS and Keck/LRIS, which, in combination with the literature, brings the spectroscopic completeness of the 2--8 keV sample to 62%. We also make optical spectral classifications and estimate photometric redshifts for the sources without spectroscopic redshifts. We then determine hard X-ray luminosity functions (XLFs) for the full sample of Active Galactic Nuclei (AGNs), as well as for the broad-line AGNs (BLAGNs) and the non-BLAGNs separately. Our XLF for the full sample is in good agreement with the literature, showing relatively strong evolution over the redshift range $0.25\le z < 4$. The XLFs for the BLAGNs and the non-BLAGNs imply distinct evolution with redshift, with BLAGNs becoming increasingly dominant at higher redshifts and X-ray luminosities.