The SWIFT AGN and Cluster Survey I: Number Counts of AGN and Galaxy Clusters

Abstract

The Swift AGN and Cluster Survey (SACS) uses 125 deg^2 of Swift XRT serendipitous fields with variable depths surrounding gamma-ray bursts to provide a medium depth (4e-15 erg/s/cm^2) and area survey filling the gap between deep, narrow Chandra/XMM-Newton surveys and wide, shallow ROSAT surveys. Here we present a catalog of 22,563 point sources and 442 extended sources and examine the number counts of the AGN and galaxy cluster populations. SACS provides excellent constraints on the AGN number counts at the bright end with negligible uncertainties due to cosmic variance, and these constraints are consistent with previous measurements. We use Wise mid-infrared (MIR) colors to classify the sources. For AGN we can roughly separate the point sources into MIR-red and MIR-blue AGN, finding roughly equal numbers of each type in the soft X-ray band (0.5-2 keV), but fewer MIR-blue sources in the hard X-ray band (2-8 keV). The cluster number counts, with 5% uncertainties from cosmic variance, are also consistent with previous surveys but span a much larger continuous flux range. Deep optical or IR follow-up observations of this cluster sample will significantly increase the number of higher redshift (z > 0.5) X-ray-selected clusters.

44 pages, 18 figures, 12 tables, Accepted by ApJS

References in corpus (11)

• The XMM-Newton Serendipitous Survey. V. The Second XMM-Newton Serendipitous Source Catalogue
• The XMM-Newton wide-field survey in the COSMOS field: VI. Statistical properties of clusters of galaxies
• A GMBCG Galaxy Cluster Catalog of 55,424 Rich Clusters from SDSS DR7
• The 400 square degrees ROSAT PSPC galaxy cluster survey: Catalog and statistical calibration
• Chandra Multiwavelength Project X-ray Point Source Number Counts and the Cosmic X-ray Background
• A Chandra Search for Coronal X Rays from the Cool White Dwarf GD 356
• The Mid-Infrared Properties of X-ray Sources
• Differential X-ray Absorption and Dust-To-Gas Ratios of the Lens Galaxies SBS0909+523, FBQS0951+2635, and B1152+199
• The Swift X-ray Telescope Cluster Survey: data reduction and cluster catalog for the GRB fields
• The Swift X-ray Telescope Cluster Survey III: Cluster Catalog from 2005-2012 Archival Data
• EXSdetect: an end-to-end software for extended source detection in X-ray images: application to Swift-XRT data

Cited by in corpus (2)

• Lower AGN Abundance in Galaxy Clusters at z < 0.5
• XMM-Newton view of X-ray overdensities from nearby galaxy clusters: the environmental dependencies