Chandra Source Catalog Release 2.0 - The State of the Art Serendipitous X-ray Source Catalog
Abstract
By combining Chandra's sub-arcsecond on-axis spatial resolution and low instrumental background with consistent data processing, the Chandra Source Catalog (CSC) delivers a wide variety of uniformly calibrated properties and science ready data products for detected sources over four dex of fluxes. The second major release of the catalog, CSC 2.0, roughly triples the size of the previous catalog to more than 315,000 unique X-ray sources on the sky, allowing statistical investigations of large samples of objects using the catalog, as well as individual source studies. The sensitivity limit for compact sources in CSC 2.0 is significantly improved by using a two-stage approach that involves co-adding multiple observations of the same field prior to source detection, and then using an optimized source detection method. This combination yields a point source detection threshold of ~5 net counts on-axis for exposures shorter than ~15 ks. The implemented Bayesian aperture photometry code produces robust photometric probability density functions (PDFs) in crowded fields, even for low count detections. CSC 2.0 also adds a Bayesian Blocks analysis of the multi-band aperture photometry PDFs to identify multiple observations of the same source that have similar photometric properties, and therefore can be analyzed simultaneously to improve S/N. We discuss these and other updates that significantly enhance the scientific utility of CSC 2.0 when compared to the previous catalog, briefly discuss the catalog statistical characterization, and consider further enhancements to be included in future catalog releases. This work has been supported by NASA under contract NAS 8-03060 to the Smithsonian Astrophysical Observatory for operation of the Chandra X-ray Center.
- Publication:
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American Astronomical Society Meeting Abstracts #233
- Pub Date:
- January 2019
- Bibcode:
- 2019AAS...23337901E