Table · dataset · 2026
HEAO 1 A4 Spectra
Listed in IVOA Registry (Virtual Observatory)
The UCSD/MIT Hard X-Ray and Low-Energy Gamma-Ray Instrument, A4, was flown on the HEAO 1 satellite, between August 1977 until January 1979.
Description
The experiment consisted of a collection of collimated sodium iodide scintillators, two of which the Low Energy detectors (LED, LED-3 and LED-6), were optimized for the lower energy part of the hard X-ray range between 13 to 180 keV. The first 6-months of mission were dedicated to an all-sky scan after which a pointing phase started.
In pointing mode the A4-LED instrument look axis was kept in a 1 deg dead band centered on the target position. Instead in the "ping-pong" mode the look axis was regularly alternated with a secondary target a few degrees away, usually for background determination. This database table accesses the spectra (and associated files) obtained from the A4-LED detectors in the ping-pong mode.
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This is a service provided by NASA HEASARC .
Links
Where it is published
- Reference page heasarc.gsfc.nasa.gov/W3Browse/all/a4spectra.html ↗
landing page · from IVOA Registry
Catalogue records · 2
- VOResource record dc.g-vo.org/oai.xml?verb=GetRecord&metadataPrefix=ivo_vor&identifier=ivo%3… ↗
metadata API · from IVOA Registry
- Registry record (GAVO) dc.g-vo.org/I/nasa.heasarc/a4spectra ↗
catalogue entry · from IVOA Registry
Topics
- Stated by source
- X-Ray
- From keywords
- Astronomy & Astrophysics
- Inferred from text
- Tabular 65%
Provenance · 1 source records, 8 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| IVOA Registry (Virtual Observatory) | ivo://nasa.heasarc/a4spectra | 15 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| access_level | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[field].local:field:astronomy | mapping · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].ivoa_waveband:x-ray | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| concepts[modality].local:modality:tabular | enrichment · IVOA Registry | keyword-concept-rules@1.0.0 | title+description (65%) |
| description | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_description |
| publication_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 | |
| title | source · IVOA Registry | connector:ivoa_registry@1.0.0 | rr.resource.res_title |
| updated_date | source · IVOA Registry | connector:ivoa_registry@1.0.0 |