3C273 Revisited - Confirmation by Cos-B of High Energy Gamma-Ray Emission
Publication date: 15 January 1981
Authors: Bignami, G.F., et al.
Journal: Astronomy and Astrophysics
Copyright: European Southern Observatory
The results of a second observation in the Virgo region by the ESA COS-B satellite are presented. The presence of a high-energy (50-800 MeV) Gamma-radiation source is confirmed, and its position is consistent with 3C273. The error box at the 90% confidence level containing the quasar is ~2.5 square degrees and the probability of a change coincidence of the gamma-ray source with 3C273 is approximately 10-3. No variation of the gamma-ray fluxes between the two observations in July 1976 and June 1978 is observed within the ~50% uncertainty. Spectral y-ray data for the total 3C273 data set are presented and compared with low and high-energy X-ray contemporary measurements. Recent Einstein Observatory X-ray data on the short term variability of the central part of the QSO are used to show that, within reasonable assumptions, the photon-photon interaction excludes the gamma-ray source from coinciding with the variable X-ray source, thus ruling out comptonisation models for the production of energetic photons.Link to publication