Chandra Announcement: Chandra Source Catalog 2.1.1 Update

[Tingle, Evan]

CHANDRA SOURCE CATALOG 2.1.1 UPDATE

 

The Chandra Source Catalog (CSC), described at https://cxc.cfa.harvard.edu/csc is the definitive catalog of X-ray sources detected by the Chandra X-ray Observatory. The current release includes measured and derived properties for 407,806 unique compact and extended X-ray sources across the sky and more than 1.3 million X-ray detections.

Chandra Source Catalog (CSC) version 2.1.1 is an overlay release that resolves four issues identified in CSC 2.1:

1. Source names in the Master Sources Table for 400 sources that had been previously identified and published in CSC 2.0 were incorrect in CSC 2.1. These source names are corrected in CSC 2.1.1. Most of the affected sources are located in the vicinity of SNR E0102-72.3. A list of corrected source names is available on the catalog website at https://cxc.cfa.harvard.edu/csc2.1/files/CorrectedNamesCSC21.txt.

2. Some properties (primarily aperture photometry properties and properties derived from them, such as hardness ratios and temporal variability) for approximately 7,000 sources in the Master Sources Table and associated detections in the Stacked Observation Detections Table may be incorrectly set to NULL in some energy bands in CSC 2.1. This occurs for master sources and stacked observation detections for which one or more ACIS observations has energy bands truncated by onboard PHA filters. These source properties are correctly populated in CSC 2.1.1. Most of the affected sources are located in the vicinity of Sgr A*.

3. For highly extended (convex hull) detections listed in the Per-Observation Detections Table, the relative astrometry offsets deltax and deltay were incorrectly reported in pixels rather than arcseconds. These properties are correctly reported in arcseconds in CSC 2.1.1.

4. The individual observation manual astrometry flag listed in the Per-Observation Detections Table may have been incorrectly set to FALSE if the detection was originally identified in CSC 2.0. These flags are correctly set in CSC 2.1.1.