X-ray intrinsic luminosity in the 2–10 keV band versus rest frame 1.4 GHz radio luminosity for our sample. Left: Sources are color-coded by the source type. NL-AGN, BL-AGN, ETG and ELG are indicated by blue, red, orange and green symbols, respectively. The light-gray symbols mark the sources without a spectroscopic classification. Circles mare the radio detected sources, while ⊤ mark the 3σ upper limits for the undetected ones. Notable sources, that are the z = 6.3 QSO and the z = 1.7 FRII galaxy, are labeled in the figure. The solid orange, cyan and black lines are the correlations found in this work for ETG, AGN and combined ETG/AGN samples, respectively. The dashed magenta line is the Panessa et al. (2015) correlation found for local Seyfert galaxies (slope ~1.1), while the blue dashed line is the relation for 0 ≲ z ≲ 1.3 SFGs (Mineo et al. 2014). The dashed green line is the relation found for z ~ 0.1−2 RL AGN by Fan & Bai (2016). All the relations are plotted in the X-ray luminosity range in which they have been derived. Typical uncertainties on the radio (X-ray) luminosity is indicated by the vertical (horizontal) error bar in the bottom-right corner. Right: same as left panel, except that sources are color coded by their redshift (right color-bar). Here we only show the correlation we derived for the combined ETG/AGN sample (black solid line). The black dashed line marks the log(L_R/L_X) = −3.5 relation, set as the threshold between RL and RQ AGN (see text).