2016ApJ...818..185F

We find that the young radio sources (gigahertz-peaked spectrum and compact steep spectrum radio sources) follow in the radio/X-ray correlation with b = 0.61 ± 0.07 (L_R ∝ L_X^b), and the fundamental plane of black hole activity with the form log L_R = 0.58_–0.03^+0.03logL_x + 0.42 log_–0.07^+0.09 and the intrinsic scatter σ = 0.29. The flatter coefficient between radio and X-ray bands denies the jet origin of the X-ray emission in these types of sources. Meanwhile, the higher ratio of X-ray luminosity to Eddington luminosity (L_X/L_Edd) suggests that the X-ray emission is produced by the hot corona coupling with the standard thin disk. The deviation with the radiative efficient fundamental plane proposed by Dong et al. is mainly due to the extended radio emission in young radio sources. This fundamental plane manifests that even the kiloparsec-scaled radio emission has a tight connection with the accretion process, and could be suitable for the radio-loud active galactic nuclei whose radio and X-ray emission are dominated by the extended jets and the radiative efficient accretion flow, respectively. Otherwise, the high-excitation galaxies and low-excitation galaxies do not have obvious distinctions in the radio/X-ray correlation and the fundamental plane.