ON A NONTHERMAL ORIGIN OF STEEP FAR-INFRARED TURNOVERS IN RADIO-QUIET ACTIVE GALACTIC NUCLEI

A nonthermal origin of the FIR-turnover that appears to be common in Seyfert galaxies and radioweak quasars is investigated in this paper. If a double power law in the electron energy distribution accounts for turnovers steeper than a 2.5 powerlaw in the observed synchrotron emission, we note that the observations of the Seyfert galaxies Mrk 1014, I Zw 1 and NGC 4151 require differences in the electron power law energy indices of larger than 2.4 and 4.6, respectively. One rather likely scenario in the nuclear regions of active galaxies is a combination of influences like stochastic acceleration and Coulomb interaction losses to produce the resulting electron energy distribution; this combination of processes readily leads to a concave emission spectrum as required by the observations. We then proceed to demonstrate that this rather general model is capable of reproducing the observations quantitatively.