Energetics of TeV Blazars and Physical Constraints on Their Emission Regions

Using multi-frequency spectra from TeV blazars in quiescent states, we obtainthe physical parameters of the emission region of blazars within the frameworkof the one-zone synchrotron self-Compton (SSC) model. We numerically calculatethe steady-state energy spectra of electrons by self-consistently taking intoaccount the effects of radiative cooling with a proper account of theKlein-Nishina effects. Here electrons are assumed to be injected with apower-law spectrum and to escape on a finite time scale, which naturally leadsto the existence of a break energy scale. Although we do not use timevariabilities but utilize a model of electron escape to constrain the size ofthe emission region, the resultant size turns out to be similar to thatobtained based on time variabilities. Through detailed comparison of thepredicted emission spectra with observations, we find that for Mrk 421, Mrk501, and PKS 2155--304, the energy density of relativistic electrons is aboutan order of magnitude larger than that of magnetic fields with an uncertaintywithin a factor of a few.Comment: Accepted for publication in Ap