SIMBAD references

During the Compton Gamma-Ray Observatory (CGRO) observations made in Phase I, II, III, and IV/Cycle 4 in the years 1991 to 1995, the region on the sky including the radio galaxy Centaurus A was in the wide field-of-view of COMPTEL in 15 pointings of various durations. The analysis of the COMPTEL data obtained during these 15 pointings shows emission consistent with the position of Cen A and we detected Cen A in two emission states (intermediate and low). Our data do not require, but also cannot rule out, that emission from a nearby X-ray source (MS1312.1-4221) contributes to the measured flux. But it is unlikely, that the high flux observed in the energy band 3-10MeV during Phase II of the COMPTEL observations, is due to a significant contribution of this source. The spectra in the COMPTEL energy range 0.75-30MeV are consistent with the Centaurus A spectra in the energy range 0.05-4MeV from OSSE and the 0.1-1GeV data points from EGRET, both instruments also on board CGRO. The spectral form differs between the two observed emission states and we derive a γ-ray luminosity in the total energy band from 50keV to 1GeV of 5x10⁴²erg/s and 3x10⁴²erg/s for isotropical emission in the the intermediate and low emission state, respectively. The inclusion of the contemporaneous OSSE and EGRET spectra stretches the covered energy range in this observations over almost five decades and puts hard constraints on models for the γ-ray emission of this AGN.