Uhuru Fourth Catalog: 339 X-ray Sources Observed 1970-1973

339 X-ray sources were cataloged from observations by the Uhuru satellite between 1970 and 1973. The catalog includes positional error boxes, intensities, and cross-identifications with optical and radio counterparts. NASA's HEASARC created this online version in 2003, based on the original published catalog.

Use Cases

• Classifying X-ray source types based on listed categories like binary stellar systems and Seyfert galaxies.
• Cross-matching celestial objects using the catalog's positional information and alternative names.
• Analyzing historical X-ray astronomy data based on the 2-6 keV intensity measurements.
• Studying the spatial distribution of early-detected X-ray sources from a defined observational period.

Strengths

• Catalog contains 339 distinct X-ray sources, providing a foundational early survey.
• Observations span 429 days between 1970-12-12 and 1973-03 18, offering a defined temporal baseline.
• Includes 90% confidence error boxes and cross-identifications, aiding source verification.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• The original ADC table differs from the published version in comments and some names/positions.
• Row count is unknown, which may limit suitability assessment.

Provenance

Source

NASA HEASARC, based on the original Uhuru (SAS A) satellite data.

Collection Method

Data from repeated satellite scans, superposed using onboard magnetometers and Sun sensor data.

Time Range

1970-12-12 to 1973-03-18 (with a gap in 1972).

Freshness

Last updated 2026-03-13 18:53:12.011854; freshness should be verified.

Geography

Celestial (sky survey).