Chandra Source Catalog: 407,806 X-ray Sources from Chandra Observatory

407,806 unique compact and extended X-ray sources are cataloged in this release from the Chandra X-ray Observatory. The Chandra Source Catalog version 2.1.1, updated in October 2024, provides over 100 uniformly calibrated positional, spatial, photometric, spectral, and temporal properties for each source, derived from 1,304,376 individual observation detections through the end of 2021. It is produced by the Chandra X-ray Center at the Harvard-Smithsonian Center for Astrophysics.

Use Cases

• Statistical analysis of large X-ray source samples based on the catalog's uniform properties.
• Individual source studies in the 'Master Sources' table based on detailed positional and photometric data.
• Spectral shape discrimination using X-ray color-color diagrams based on measurements in defined energy bands.
• Analysis of highly extended sources based on the included photometric properties and surface brightness polygons.

Strengths

• Contains 407,806 unique X-ray sources and 1,304,376 individual observation detections.
• Provides over 100 tabulated properties per source, each with confidence intervals and measured in multiple energy bands.
• Uses a two-stage detection approach achieving a sensitivity limit of ~5 net counts for compact sources.
• Includes Bayesian aperture photometry producing robust probability density functions, even for low-count detections.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Data coverage is limited to observations released publicly through the end of 2021.

Provenance

Source

Chandra X-ray Center at the Harvard-Smithsonian Center for Astrophysics.

Collection Method

Data processing and source detection from Chandra ACIS and HRC-I imaging observations.

Time Range

Observations released publicly through the end of 2021.

Freshness

Catalog version 2.1.1 was updated on 2024 October 18.

Geography

Sky coverage from the Chandra X-ray Observatory.