GALEX/SDSS Quasar Catalog: UV and Optical Properties for 6,371 Objects

6,371 quasars from the Sloan Digital Sky Survey Data Release 3 were matched with UV observations from the Galaxy Evolution Explorer General Data Release 1. The catalog, created by NASA HEASARC in October 2009, contains 5,380 near-UV detections and 3,034 objects with both near-UV and far-UV detections, covering a redshift range up to z ~ 3.4. It provides spectral energy distributions from ~350 to 9000 Angstroms in the rest frame, enabling analysis of UV-optical color properties and luminosity trends.

Use Cases

• Analyzing the relationship between UV-optical color and quasar luminosity based on the constructed median SEDs.
• Studying the detection fraction of optically selected quasars in the UV as a function of redshift and optical brightness.
• Investigating potential reddening of quasars due to line-of-sight absorption or dust using UV-optical color-color space.
• Modeling attenuation by intervening Lyman-absorbing clouds using UV-optical flux as a function of redshift.

Strengths

• Large sample of 6,371 quasars with matched UV and optical data.
• 84% (5,380) of the sample has near-UV detections, providing substantial coverage.
• Spectral energy distributions cover a broad wavelength range from ~350 to 9000 Angstroms in the rest frame.
• Positions are consistent between GALEX and SDSS with an rms scatter of 0.6 - 0.7 arcseconds.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Last updated 2026-03-13 18:41:22.000366; freshness should be verified.

Provenance

Source

National Aeronautics and Space Administration (NASA HEASARC).

Collection Method

Cross-match analysis of quasars from the Sloan Digital Sky Survey Data Release 3 and the Galaxy Evolution Explorer General Data Release 1.

Freshness

Last updated 2026-03-13 18:41:22.000366; freshness should be verified.