Energetics of TeV Blazars and Physical Constraints on Their Emission Regions

Using multifrequency spectra from TeV blazars in quiescent states, we obtain the physical parameters of the emission region of blazars within the framework of the one-zone synchrotron self-Compton model. We numerically calculate the steady state energy spectra of electrons by self-consistently taking into account the effects of radiative cooling with a proper account of the Klein-Nishina effect. Here electrons are assumed to be injected with a power-law spectrum and to escape on a finite timescale, which naturally leads to the existence of a break energy scale. Although we do not use time variabilities but use a model of electron escape to constrain the size of the emission region, the resultant size turns out to be similar to that obtained based on time variabilities. Through detailed comparison of the predicted emission spectra with observations, we find that for Mrk 421, Mrk 501, and PKS 2155-304, the energy density of relativistic electrons is about an order of magnitude larger than that of magnetic fields with an uncertainty within a factor of a few.