SDSS/UKIDSS Matched Quasar Catalog with 130,000 Candidates

NASA HEASARC provides a catalog of over 130,000 quasar candidates with matched optical and near-infrared photometry. The data results from matching the Sloan Digital Sky Survey (SDSS) DR6 Photometric Quasar catalog to the UKIRT Infrared Digital Sky Survey (UKIDSS) Large Area Survey Data Release 3, covering approximately 1200 square degrees. This table was created by the HEASARC in September 2012 based on an external catalog file.

Use Cases

• Train models for quasar candidate classification based on nine-band optical and NIR photometry.
• Analyze color-redshift relationships for quasars using the matched ugrizYJHK photometric bands.
• Study systematic astrometric offsets between major sky survey catalogs.
• Assess survey completeness and limiting magnitude for quasar detection projects.

Strengths

• Contains 130,827 objects with detections in one or more near-infrared bands.
• Provides precise positional matching with standard deviations of ~0.13 arcseconds in RA and Dec.
• Includes 42,133 objects with full nine-band (ugrizYJHK) photometry for detailed analysis.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The majority (~85%) of SDSS objects were not matched due to lack of UKIDSS LAS coverage, indicating incomplete spatial overlap.

Provenance

Source

National Aeronautics and Space Administration (NASA HEASARC), based on CDS Catalog J/AJ/141/105.

Collection Method

Catalog matching of the SDSS DR6 Photometric Quasar catalog to UKIDSS LAS Data Release 3.

Time Range

null

Freshness

Last updated 2026-03-13 19:51:38.733298; freshness should be verified.

Geography

Sky survey covering approximately 1200 square degrees.