Hamburg/RASS Catalog: X-Ray Sources at High Galactic Latitude

The Hamburg/ROSAT All-Sky Survey (RASS) Catalog lists 5,341 X-ray sources from the ROSAT Bright Source Catalog, covering approximately 10,000 square degrees of the sky at galactic latitudes |b| >= 30 degrees and declination Dec >= 0 degrees. NASA HEASARC produced this table in February 2005 based on source data from the Centre de Données astronomiques de Strasbourg (CDS). For 82% of the selected sources, an optical identification was provided, with AGN representing the largest group at ~42%.

Use Cases

• Selecting complete samples of X-ray emitters based on the catalog's classification of sources into AGN, stars, galaxies, and clusters.
• Cross-matching X-ray source positions with optical survey data based on the described use of digitized Hamburg Quasar Survey plates.
• Analyzing the distribution and properties of high-galactic latitude X-ray sources based on the catalog's coverage of ~10,000 square degrees.
• Studying the identification success rate for X-ray sources based on the stated 82% identification rate and the ~3% with no visible optical counterpart.

Strengths

• Covers 5,341 X-ray sources from a well-defined survey (ROSAT Bright Source Catalog).
• Provides optical identifications for 82% of the selected sources.
• Includes classification breakdowns: ~42% AGN, ~31% stars, ~4% galaxies, ~5% clusters.
• Based on digitized optical plates from the Hamburg Quasar Survey with limiting magnitudes of 18.5 and 20.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Data may reflect observational bias inherent to the specific ROSAT survey and optical plate coverage.

Provenance

Source

NASA HEASARC, based on CDS Catalog table J/A+A/406/353/x-ray.dat.

Collection Method

Optical identification using blue Schmidt prism and direct plates from the Hamburg Quasar Survey.

Time Range

Based on the ROSAT All-Sky Survey (1990-1991).

Freshness

Last updated 2026-03-13 17:34:53.991901; freshness should be verified.

Geography

Sky coverage with galactic latitude |b| >= 30 degrees and declination Dec >= 0 degrees (~10,000 square degrees).