2.3. Blazar Variability

Variability properties of blazars are distinct from those of other non-beamed AGNs and should be mentioned separately. Blazars are characterized by extreme variability at all wavelengths. Unlike radio-quiet quasars or Seyfert galaxies, significant infrared and radio continuum variability is observed in blazars. Furthermore, the polarization of the continuum radiation is also significant (i.e., greater than a few percent), and the degree of polarization and amplitude of variability correlate with luminosity, which is the opposite case for non-blazars. Blazars are also the only sources detected at TeV energies, and the TeV fluxes can vary by as much as a factor of 10 in one day. All of these properties indicate that the continuum is dominated by emission from relativistic jets, as these characteristics suggest a non-thermal (synchrotron or inverse Compton) origin.