Discovery of soft X-ray flux from 2A 1102+384 = Markarian 421.
Abstract
During April 1976 a soft X-ray flux was detected with SAS 3 from the vicinity of 2A 1102+384. The average flux densities were 4.3 x 10 to the -11th and 14 x 10 to the -11th erg/sq cm per sec in the energy bands 0.1-0.28 keV and 1-6 keV, respectively. There is an indication of variability over about 0.5 day in the lowest energy band. An upper limit of 3 x 10 to the 20th H atoms per sq cm is found for the gas column density to the X-ray source. In May 1978, observations with the modulation collimators of SAS 3 yielded an accurate (40 arcsec error radius) position for the X-ray source (2-6 keV) at right ascension 11 h 1 m 39.7 s, declination + 38 deg 28 min 51 sec (equinox 1950). The earlier tentative identification by Ricketts et al. (1976) with the BL Lacertae object B2 1101+38 = Markarian 421 is thus confirmed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1979
- DOI:
- 10.1086/182868
- Bibcode:
- 1979ApJ...227L..63H
- Keywords:
-
- Bl Lacertae Objects;
- Elliptical Galaxies;
- Galactic Radiation;
- Radiant Flux Density;
- X Ray Sources;
- Collimators;
- Gas Density;
- Variability;
- X Ray Spectra;
- Astrophysics;
- BL Lacertae Objects:X Rays