Optically Selected Radio-Intermediate and Loud Quasars X-ray Emission Catalog

NASA's HEASARC table contains the primary sample from a 2012 study investigating X-ray properties of quasars. The catalog includes 654 optically selected radio-intermediate and radio-loud quasars with observations from SDSS, FIRST, and archival X-ray data from Chandra, XMM-Newton, and ROSAT. It provides broad coverage of the luminosity-redshift plane, with 22% of objects at high redshifts (z=2-5) and an 84% X-ray detection rate.

Use Cases

• Modeling X-ray luminosity as a function of optical/UV and radio luminosity based on the parametrization described.
• Analyzing the 'excess' X-ray brightness of radio-loud quasars relative to radio-quiet quasars as a function of radio loudness.
• Studying the distribution of quasars across the luminosity-redshift plane, including high-redshift objects.
• Comparing X-ray detection rates and properties across different observatories (Chandra, XMM-Newton, ROSAT).

Strengths

• High X-ray detection rate of 84% for the primary sample of 654 quasars.
• Broad coverage of the luminosity-redshift plane, including 22% of objects at high redshifts (z=2-5).
• Combines data from multiple modern optical (SDSS), radio (FIRST), and X-ray (Chandra, XMM-Newton, ROSAT) surveys.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Data is based on a 2012 study; freshness should be verified for current research.

Provenance

Source

National Aeronautics and Space Administration (NASA), HEASARC

Collection Method

Combined large optical (SDSS) and radio (FIRST) surveys with archival X-ray data from Chandra, XMM-Newton, and ROSAT.

Time Range

Based on archival data; specific observation dates are not provided.

Freshness

Last updated 2026-03-13 19:04:48.611112; freshness should be verified.

Geography

Astronomical observations; not geographically bound.