COMPTEL gamma-ray observations of the quasars CTA 102 and 3C 454.3
The blazar-type active galactic nuclei CTA 102 (QSO 2230+114) and 3C 454.3 (QSO 2251+158), located about 7 deg apart, were observed by the Compton Gamma Ray Observatory at four epochs in 1992. Both were detected by Energy Gamma Ray Experiment Telescope (EGRET). The combined Compton Telescope (COMPTEL) observations in the 10-30 MeV energy range clearly indicate a source of MeV emission, which is likely due to a contribution from both quasars. These observations strongly suggest that the power-law spectra measured by EGRET above approximately 50 MeV flatten at lower MeV energies. A comparison with observations at other wavelengths shows that the power spectra of CTA 102 and 3C 454.3 peak at MeV energies. This behavior appears to be a common feature of gamma-ray active galactic nuclei (AGN).
Astronomy and Astrophysics Supplement Series
European Southern Observatory (ESO)
J.J. Blom, H. Bloemen, K. Bennett, W. Collmar, W. Hermsen, M. McConnell, V. Schönfelder, J.G. Stacy, H. Steinle, A. Strong, and C. Winkler. COMPTEL GAMMA-RAY OBSERVATIONS OF THE QUASARS CTA 102 AND 3C 454.3. 1995, Astron. Astrophys., 295, 330.