Statistical Characterization of the Chandra Source Catalog

TL;DR

This paper details the statistical characterization of the first release of the Chandra Source Catalog, assessing its completeness, sensitivity, and accuracy through comparisons and simulations to ensure scientific reliability.

Contribution

It introduces a comprehensive characterization process for the CSC, including comparisons with other catalogs and extensive simulations, to evaluate its statistical properties.

Findings

Assessment of catalog completeness and sensitivity.

Quantification of false source rates.

Validation of source property accuracy.

Abstract

The first release of the Chandra Source Catalog (CSC) contains ~95,000 X-ray sources in a total area of ~0.75% of the entire sky, using data from ~3,900 separate ACIS observations of a multitude of different types of X-ray sources. In order to maximize the scientific benefit of such a large, heterogeneous data-set, careful characterization of the statistical properties of the catalog, i.e., completeness, sensitivity, false source rate, and accuracy of source properties, is required. Characterization efforts of other, large Chandra catalogs, such as the ChaMP Point Source Catalog (Kim et al. 2007) or the 2 Mega-second Deep Field Surveys (Alexander et al. 2003), while informative, cannot serve this purpose, since the CSC analysis procedures are significantly different and the range of allowable data is much less restrictive. We describe here the characterization process for the CSC. This process includes both a comparison of real CSC results with those of other, deeper Chandra catalogs of the same targets and extensive simulations of blank-sky and point source populations.