X-Ray Emission from LSI+61 303
Abstract
G. F. Bignami and P. A. Caraveo, Istituto di Fisica Cosmica, Milan; R. C. Lamb, Iowa State University; and T. H. Markert, Massachusetts Institute of Technology, report the preliminary results of an observation with the Einstein Observatory of the field containing LSI+61 303, a radio star with a period of 26.45 days (cf. IAUC 3164, 3170, 3180, 3210 and 3464). The observation was performed with the IPC instrument on 1979 Feb. 3 for a total of ~ 830 s useful time. A clear point source (~ 60 counts over a background of 6) was detected with a best position at R.A. = 2h36m42s, Decl. = +61o01'20" (equinox 1950.0) and an estimated error-circle radius of ~ 1'. The energy flux from 0.2 to 4.5 keV is ~ 2.3 x 10-**19 J/s. The positional agreement with LSI+61 303 (the brightest object in the error circle) is good. Further Einstein observations recently obtained with the HRI instrument will be used to reduce the positional uncertainty to a few seconds of arc. The reported observation is part of a survey conducted with the Einstein Observatory of the error circles of selected gamma-ray sources seen above 100 MeV. LSI+61 303 lies within the 1o-radius error circle of CG 135+01 and may be causally related to it.
- Publication:
-
International Astronomical Union Circular
- Pub Date:
- September 1980
- Bibcode:
- 1980IAUC.3518....2B