Data · dataset · 2025
Einstein IPC Ultrasoft Sources Catalog
Listed in NASA Data Portal
A survey of the entire Einstein IPC database (a total of 5934 sources) has been carried out in order to select objects with strong components of ultrasoft X-ray emission (i.e., emission below 0.5 keV).
Description
The selection criteria were based on ratios of counts within three broad energy bands (i.e., X-ray "colors"). A total of 516 objects have been selected, with 202 (39%) having been identified through correlations with other databases.
Of the currently identified objects, 45% are active galactic nuclei, 28% are stellar objects, 6% are "normal" galaxies and galaxy clusters, and the remaining 21% are "nonstellar" Galactic objects such as cataclysmic variables, pulsars, and white dwarfs. The selection of sources for this survey was based on the analysis of counts in three broad energy bands defined as C1=0.16-0.56 keV, C2=0.56-1.08 keV, and C3= 1.08-3.5 keV.
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Ratios of these three bands constituted X-ray 'colors' which in turn were used to estimate the shape of the spectrum over the IPC bandpass. Based on models of X-ray spectra folded through the IPC response function, the following criteria were determined for the selection of ultrasoft sources: C1>0 and R1=C2/C1<0.36. These criteria guarantee an intrinsically soft X-ray spectrum that can be modeled by blackbody temperatures kT<50 keV, power-law spectral indices of >=2, or thermal plasma temperatures T<1 MK (million K).
Details of the data analysis can be found in the Thompson et al. (1998) reference. This database was created by the HEASARC in April 1999 based on tables provided by the catalog authors to the CDS/ADC. This is a service provided by NASA HEASARC .
Links
Get the data
- Resource heasarc.gsfc.nasa.gov/W3Browse/all/ipcultsoft.html ↗
download · from data nasa gov
- Resource heasarc.gsfc.nasa.gov/xamin/vo/cone?showoffsets=&table=ipcultsoft ↗
download · from data nasa gov
Where it is published
- NASA Data Portal dataset page data.nasa.gov/dataset/einstein-ipc-ultrasoft-sources-catalog ↗
landing page · from data nasa gov
Catalogue records · 1
- CKAN API data.nasa.gov/api/3/action/package_show?id=fd6675c3-61c8-4b57-9c75-2b728a310… ↗
metadata API · from data nasa gov
Provenance · 1 source records, 6 field assertions
| Source | Key | Last seen | Raw |
|---|---|---|---|
| NASA Data Portal | fd6675c3-61c8-4b57-9c75-2b728a310d1b | 9 d ago | JSON v1 |
| Field | Assertion | Extractor | Evidence |
|---|---|---|---|
| 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 |