2XMMi-DR3: Ensemble X-Ray Variability of AGN Quasars

412 quasars observed by XMM-Newton from 2 to 25 epochs each provide 1,376 observations for analyzing X-ray variability. The data, covering redshifts from ~0.2 to ~4.5 and luminosities from ~10^43 to ~10^46 erg/s, was created by the HEASARC in April 2012. It uses the structure function method to analyze ensemble variability across a large sample of active galactic nuclei.

Use Cases

• Modeling the power-law relationship of structure function with time lag based on the reported SF ~ tau^0.1.
• Investigating the anti-correlation between X-ray variability and luminosity described in the study.
• Testing for evidence of an intrinsic increase in X-ray variability with redshift as suggested by the authors.
• Comparing variability properties of high-luminosity AGNs with lower-luminosity samples where a break in the structure function is reported.

Strengths

• Includes 412 unique quasars with multi-epoch observations, totaling 1,376 X-ray observations.
• Covers a wide redshift range (~0.2 to ~4.5) and luminosity range (~10^43 to ~10^46 erg/s).
• Derived from the 2XMMi-DR3 catalog, which contains 353,191 detections from 262,902 unique X-ray sources.
• Sources were cross-matched with the SDSS Quasar Catalog DR7 for redshift and spectral classification.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count for the specific analysis sample is unknown, which may limit suitability assessment.
• The catalog includes observations made between 2000-02-03 and 2008-10-08; data freshness should be verified for contemporary research.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Serendipitous source extraction from the 2XMMi-DR3 XMM-Newton catalog, cross-correlated with the SDSS Quasar Catalog DR7.

Time Range

Observations made between 2000-02-03 and 2008-10-08.

Freshness

Last updated 2026-03-13 20:13:05.975309; freshness should be verified.

Geography

Covers a net sky area of ~504 square degrees from XMM-Newton observations.