HEAO A-2 soft X-ray source catalog.
Abstract
The HEAO A-2 low energy X-ray detectors have surveyed over 95% of the sky in the spectral bands 0.18-0.44 and 0.44-2.8 keV, down to a typical limiting sensitivity of 1 x 10 to the -11th and 3 x 10 to the -11th ergs per sq cm per sec in each band, respectively. Using a significance criterion of 6 sigma for existence, 114 sources are cataloged, of which 54 were previously undiscovered and 32 remain unidentified. The catalog contains a listing of all counterpart identifications and a cross-reference to all HEAO 1 A-2 low energy detector team publications on the catalog sources complete through the end of 1981. Supplementary material allows the estimation of spectral parameters for the spectral models from the observed intensities. Simple graphs allow the extraction of energy fluxes at the earth, both with and without the effects of interstellar absorption. The angular distribution of the cataloged sources in the 0.44-2.8 keV band is concentrated toward the galactic plane and resembles that seen at higher energy. The distribution in the 0.18-0.44 keV band is more uniform and contains many more newly discovered and unidentified sources.
- Publication:
-
The Astrophysical Journal Supplement Series
- Pub Date:
- January 1983
- DOI:
- 10.1086/190838
- Bibcode:
- 1983ApJS...51....1N
- Keywords:
-
- Astronomical Catalogs;
- Heao 1;
- X Ray Sources;
- Angular Distribution;
- Interstellar Extinction;
- Spectral Bands;
- Spectral Energy Distribution;
- Astronomy