LQAC-3: Large Quasar Astrometric Catalog, 3rd Release

The third release of the Large Quasar Astrometric Catalog (LQAC-3) compiles all quasars recorded up to its publication date. It was created by cross-identifying nine source catalogs and includes precise ICRS equatorial coordinates, redshifts, photometry, and absolute magnitudes for its objects. The catalog is maintained by the National Aeronautics and Space Administration and was last updated in March 2026.

Use Cases

• Training models for quasar identification and classification based on photometric and redshift data.
• Analyzing the distribution and physical properties of quasars using compiled magnitudes and radio fluxes.
• Calibrating or validating celestial reference frames using the catalog's high-precision ICRS coordinates.
• Studying cosmological parameters by leveraging the catalog's standardized redshift and magnitude calculations.

Strengths

• Integrates data from nine source catalogs chosen for accuracy and object count, suggesting broad coverage.
• Coordinates are recomputed with respect to the ICRF2, indicating a high standard for astrometric precision.
• Includes cross-identification with external catalogs (2MASS, B1.0, GSC2.3) to complete photometric data.

Limitations

• Row count and dataset size are unknown, which may limit suitability assessment for large-scale projects.
• Column-level documentation is absent; field semantics must be inferred after download.
• The description references a final catalog called 'LQAC-2' containing 187,504 quasars, but the row count for LQAC-3 is not provided.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Compilation via cross-identification of nine quasar catalogs, with additional data from external photometric catalogs.

Time Range

Covers quasars recorded up to the catalog's publication date (specific range not provided).

Freshness

Last updated 2026-03-13 17:42:21.009098.

Geography

Extragalactic; celestial coordinates cover the entire sky.