MORX: 3.1 Million Optical Objects with Radio and X-Ray Associations

3,115,575 optical objects are cross-matched with major X-ray and radio surveys to calculate probable associations. The catalog, produced by NASA, includes object classifications, magnitudes, redshifts, and association likelihoods ranging from 40-100% confidence. It was last updated in March 2026.

Use Cases

• Classifying unlabeled optical objects as QSOs, galaxies, or stars based on the provided likelihoods.
• Identifying candidate double radio lobes based on the catalog's lobe pair identifiers.
• Cross-referencing astronomical objects across Chandra, XMM-Newton, NVSS, and FIRST surveys using the provided source identifiers.
• Analyzing the correlation between optical magnitudes and the presence of radio or X-ray emissions.

Strengths

• Contains 3,115,575 optical objects, providing a large-scale sample for analysis.
• Includes over 1.8 million core radio associations from the LoTSS survey and 263,649 X-ray associations from XMM-Newton.
• Provides calculated likelihoods for associations and object classifications, adding a probabilistic confidence measure.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count for the main sample is known, but the total number of rows in the downloadable file is unknown.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Uniform processing combining the largest published optical, radio, and X-ray sky catalogs.

Time Range

Likely spans the observational periods of the included surveys (e.g., ROSAT, Chandra, NVSS, VLASS).

Freshness

Last updated 2026-03-13 17:53:37.263463; freshness should be verified.

Geography

Sky survey data; spatial coverage is celestial.