CHAMP/SDSS Nearby Low-Luminosity AGN Catalog: X-ray and Optical Galaxy Data

107 nearby galaxies comprise the main sample for investigating the relationship between X-ray emission and optical galaxy evolution. The catalog combines Chandra X-ray observations with Sloan Digital Sky Survey optical data to study low-luminosity active galactic nuclei. It provides X-ray spectral fits for sources with counts ranging from 2 to 1325, offering novel constraints on accretion power decline along an evolutionary sequence.

Use Cases

• Investigating the anticorrelation between X-ray spectral slope and Eddington ratio based on Gamma and L/L_Edd measurements
• Analyzing the evolutionary sequence from HII regions to passive galaxies using combined X-ray luminosity and optical data
• Comparing accretion modes in supermassive black holes to stellar-mass X-ray binaries based on spectral characteristics
• Modeling X-ray spectral energy distributions for low-luminosity AGN using power-law fits to 0.5-8 keV spectra

Strengths

• Provides X-ray spectral fits and valid uncertainties for all galaxies, with a mean of 76 counts and median of 19 counts
• Derived from a large, homogeneously selected parent sample of 15,955 galaxies from the cross-match of ChaMP and SDSS DR4
• Focuses on a well-defined main sample of 107 X-ray detected sources with specific quality cuts (off-axis angle <0.2 degrees)

Limitations

• Column-level documentation is absent; field semantics must be inferred after download
• Row count is unknown for the full parent sample, which may limit suitability assessment
• Description metadata is limited; actual data quality requires manual inspection after download

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Cross-match of Chandra Multiwavelength Project (ChaMP) sky regions with Sloan Digital Sky Survey (SDSS) DR4 spectroscopic footprint, followed by X-ray spectral fitting

Time Range

Observations likely correspond to the ChaMP and SDSS DR4 data collection periods (circa early 2000s)

Freshness

Last updated 2026-03-13 18:59:19.265295; freshness should be verified

Geography

Astronomical sky coverage from the combined ChaMP and SDSS surveys