eRASS1: X-Ray Source Catalog from First 6 Months of eROSITA All-Sky Survey

The German eROSITA Consortium presents a catalog of nearly 930,000 X-ray sources detected in the 0.2-2.3 keV energy band, covering half the sky from the first six months of the Spektrum Roentgen Gamma satellite survey (December 2019 to June 2020). This release increases the number of known X-ray sources in published literature by more than 60% and resolves about 20% of the cosmic X-ray background in the 1-2 keV range. The catalog includes both point-like and extended sources, with validated astrometric accuracy and methods to flag potential spurious detections.

Use Cases

• Cross-match X-ray sources with optical or radio catalogs based on the provided astrometric positions.
• Analyze the population statistics of X-ray sources based on the number counts variation across the sky.
• Identify and study specific classes of celestial objects (e.g., active galactic nuclei, clusters of galaxies) from the comprehensive inventory.
• Model the cosmic X-ray background based on the resolved fraction estimated in the catalog.

Strengths

• Contains nearly 930,000 entries, increasing known X-ray sources by more than 60%.
• Provides a uniform all-sky flux limit (50% completeness) for consistent analysis.
• Astrometric accuracy was tested and validated via cross-comparison with other catalogs.
• Includes methods to identify and flag potential spurious sources, improving reliability.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown for the linked hard-band catalog (eRASS1HARD), which may limit suitability assessment.
• Data covers only half the sky (the proprietary half belonging to the German consortium).

Provenance

Source

German eROSITA Consortium, via the HEASARC and CDS.

Collection Method

Data acquired by the eROSITA telescope array aboard the Spektrum Roentgen Gamma satellite.

Time Range

First six months of survey operations (eRASS1), completed June 2020.

Freshness

Last updated 2026-03-13 17:19:24.535065; freshness should be verified.

Geography

Half the celestial sky (the proprietary half with data rights held by the German eROSITA Consortium).