HEAO 1 A1: X-Ray Source Catalog with 842 Sources from 1977 Sky Survey

The first six months of data from the 1977 HEAO-1 satellite mission, which completed a full sky scan. This catalog lists positions and intensities for 842 X-ray sources, cross-referenced with literature, and was published by NASA HEASARC in 1984 with a minor revision in 2004.

Use Cases

• Identify and catalog X-ray sources based on positional data and flux intensities.
• Cross-reference astronomical objects by matching catalog positions with published literature.
• Analyze survey completeness for X-ray sources at specific flux levels, such as 1.5 microJanskies.
• Study the population of unidentified sources, which constituted half the catalog at publication.

Strengths

• Contains data for 842 distinct X-ray sources with positions and intensities.
• Catalog is more than 90% complete at a defined flux level of 1.5 microJanskies for a Crab-like spectrum.
• Includes cross-referencing with published literature and a list of 654 optical object identifications.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Data is from a specific 6-month period in 1977; newer surveys may have superseded some findings.
• Half of the sources were unidentified at the time of the 1984 publication.

Provenance

Source

National Aeronautics and Space Administration (NASA HEASARC)

Collection Method

Detected with the NRL Large Area Sky Survey Experiment aboard the HEAO-1 satellite.

Time Range

First six months of the HEAO-1 mission (1977).

Freshness

Last updated 2026-03-13 19:45:33.008628; freshness should be verified

Geography

Entire sky.