The X-ray emission in young radio AGNs
  In this work, we investigated the X-ray emission for a sample of young radio
AGNs by combining their data from Chandra/XMM-Newton and at other wavebands. We
find strong correlations between the X-ray luminosity $L_{\rm X}$ in 2$-$10 keV
and the radio luminosities $L_{\rm R}$ at 5 GHz for VLBI radio-core, VLA
radio-core and FIRST component, indicating that both pc- and kpc-scale radio
emission strongly correlate with X-ray emission in these sources. We find
approximately linear dependence of radio on X-ray luminosity in the sources
with radiative efficient accretion flows (i.e., the Eddington ratio $R_{\rm
edd} \gtrsim 10^{-3} $) with b $\sim$ 1 ($L_{\rm R}$ $\propto$ $L_{\rm X}
^{b}$) and $\xi_{\rm RX}$ $\sim$ 1 in fundamental plane using VLBI data, where
the dependence is consistent with the re-analysed result on the previous study
in \cite{2016ApJ...818..185F} at $R_{\rm edd} \gtrsim 10^{-3}$, however is
significantly deviated from the theoretical prediction of accretion flow as the
origin of X-ray emission. In contrast to radio-quiet quasars, there is no
significant correlation between $\Gamma$ and Eddington ratio. Our results seem
to indicate that the X-ray emission of high-accreting young radio AGNs may be
from jet. We constructed the SEDs for 18 sources (most are in radiative
efficient accretion) including 9 galaxies and 9 quasars with high-quality X-ray
data, and find that the X-ray emission of most quasars is more luminous than
that of normal radio-quiet quasars. This is clearly seen from the quasar
composite SED, of which the X-ray emission is apparently higher than that of
radio-quiet quasars, likely supporting the jet-related X-ray emission in young
radio AGNs. The scenario that the X-ray emission is from self-synchrotron
Compton (SSC) is discussed.
