Data · dataset · 2025
Einstein Two-Sigma Catalog
Listed in NASA Data Portal
The X-ray sources from observations made with the Einstein Observatory (HEAO-2) Imaging Proportional Counter (IPC) that have intensities of 2-sigma or more above the background are compiled in this catalog.
Description
This catalog covers more sky at fainter flux levels than the Einstein Medium Sensitivity Survey. Fields with diffuse emission sources such as bright Abell clusters of galaxies and supernova remnants were excluded.
Thus, data within 10 degrees of the galactic plane as well as fields within the boundaries of the Magellanic Clouds were excluded. Regions crowded with galactic sources such as the Orion and Pleiades fiels were also excluded. Excluding redundant fields, this catalog covers 1850 sq. degrees of the sky.
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The generation of the Einstein Two-Sigma Catalog was described in detail by Moran et al. (1996). Please read this article carefully to ensure responsible use of the Catalog. Detailed scientific and technical questions on the contents and methodology of this catalog should be addressed to the first author, Ed Moran (edhed@igpp.llnl.gov).
In particular, it should be noted that, by design, this catalog contains a significant number of spurious sources: only 28%, or about 13,000 sources, out of the 46,000 source in the 2-sigma catalog are `real` astrophysical sources, with the remainder of the sources being spurious ones. Moran et al. show in their paper that performing cross-correlations of 2-sigma sources with other catalogs is an effective way of selecting sources in this catalog that are probably real.
This is a service provided by NASA HEASARC .
Links
Get the data
- Resource heasarc.gsfc.nasa.gov/W3Browse/all/twosigma.html ↗
download · from data nasa gov
- Resource heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets=&table=twosigma ↗
download · from data nasa gov
Where it is published
- NASA Data Portal dataset page data.nasa.gov/dataset/einstein-two-sigma-catalog ↗
landing page · from data nasa gov
Catalogue records · 1
- CKAN API data.nasa.gov/api/3/action/package_show?id=9d608240-cdb4-4f44-9d13-7ecc3c42a… ↗
metadata API · from data nasa gov
Topics
- Inferred from text
- Imaging 75%
Provenance · 1 source records, 7 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| NASA Data Portal | 9d608240-cdb4-4f44-9d13-7ecc3c42a9b7 | 11 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| concepts[modality].local:modality:imaging | enrichment · data nasa gov | keyword-concept-rules@1.0.0 | title+description (75%) |
| created_date | source · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| description | source · data nasa gov | connector:data_nasa_gov@1.0.0 | /notes |
| license_text | source · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| publication_date | source · data nasa gov | connector:data_nasa_gov@1.0.0 | |
| title | source · data nasa gov | connector:data_nasa_gov@1.0.0 | /title |
| updated_date | source · data nasa gov | connector:data_nasa_gov@1.0.0 |