Relativistic Electrons in Blazars: A Hadronic Origin?
Recent observations of blazars have established that their
gamma ray emission is associated, as a rule, with
very fast variability (as short as ~ 15 min for the
TeV photons of Mkn 421); as such, these observations push the
theoretical models for the production of the required relativistic
electrons to their limits. Herein we investigate the
possibility that ``blobs" loaded with relativistic protons
could produce such an activity. We show that, if the proton
number density in a ``blob" exceeds a certain critical value,
then reflection of its own synchrotron produced photons on
some external ``mirror", such as a line emitting cloud, can
initiate a feedback process in which the protons can lose
most of their energy content in a ``blob" crossing time,
resulting in a flare of the same duration. By performing a
dimensional analysis we find the necessary conditions for
such an instability to occur and we show that the conditions
required are consistent with those usually assumed to prevail
within the relativistic jets of this class of AGN.
File translated from TEX by TTH, version 2.32.
On 16 Jul 1999, 09:19.