Chandra COSMOS Survey: Photometric Redshifts for 1694 X-ray Sources

A catalog of photometric redshifts for 1694 Chandra X-ray Observatory sources in the central square degree of the COSMOS field. The dataset was created by the NASA HEASARC in November 2011 based on published research, and it includes revised redshifts for XMM-detected sources. The authors achieved an accuracy sigma[Delta-z/(1+Z_spec)] ~ 0.015 with a 5.8% outlier fraction by using a large spectroscopic training set and optimizing template libraries.

Use Cases

• Training and validating photometric redshift estimation models based on the described spectroscopic training set and multi-band photometry.
• Studying the correlation between X-ray luminosity and optical morphology for faint, extended sources as discussed in the description.
• Benchmarking AGN identification algorithms against the catalog's template library selection methodology.
• Analyzing the impact of deep H-band photometry on redshift accuracy for the 248 sources with significant revisions.

Strengths

• High accuracy reported: sigma[Delta-z/(1+Z_spec)] ~ 0.015 with 5.8% outliers for the full sample.
• Includes 1694 sources with photometric redshifts, providing a substantial sample for analysis.
• Methodology leverages a large spectroscopic training set and deep multi-band photometry, including H_AB = 24 mag data.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Positions were added by the HEASARC based on an assumed numbering scheme, not from the original publication.

Provenance

Source

National Aeronautics and Space Administration (NASA HEASARC)

Collection Method

Derived from Table 4 of the reference paper, with positions cross-referenced from the Chandra COSMOS Survey Point Source Catalog.

Time Range

Observational data from the Chandra COSMOS Survey.

Freshness

Last updated 2026-03-13 18:09:22.258373; freshness should be verified.

Geography

Covers the central square degree of the Cosmic Evolution Survey (COSMOS) field.