Constraints on the composition, magnetization, and radiative efficiency
  in jet of blazar
  The composition and energy dissipation in jets are two of the fundamental
questions of jet physics that are not fully understood. In this paper, we
attempt to constrain the composition, magnetization as well as radiative
efficiency for blazar with the recently released low-frequency radio catalog of
the TIFR GMRT Sky Survey at 150 MHz. The jet power estimated from the
low-frequency radio emission is much lower than that derived from spectral
energy distribution fitting assuming one proton per electron. Assuming the jet
power estimated from low-frequency radio emission is physical, the fraction of
electron/positron pairs can be constrained with $n_{\rm pairs}/n_{\rm p} \sim
10$. By comparing the power carried by magnetic field and radiation with the
jet power estimated from the low-frequency radio emission, we find both
relatively high magnetization parameter of $\sigma \sim 0.5$ and radiative
efficiency of $\eta \sim 0.4$ in the dissipation region of blazars. These
results suggest that the magnetic reconnection processes may play an important
role in the energy dissipation of blazars. We also explore the connection
between these three parameters ($n_{\rm pairs}/n_{\rm p}$, $\sigma$, and
$\eta$) and the black hole mass, disk luminosity as well as Eddington ratio. No
significant correlation is found, except that $\sigma$ shows possible
correlation with disk luminosity.
