Rest frame spectral energy distribution of PSO J0309+27 from radio to X-rays frequencies. In addition to the radio and optical photometric points, in X-rays the best-fit emission in the observed [0.5–10] keV energy band (green dotted line) with its uncertainty is shown. The optical MODS/LBT spectrum (in black) and a quasar template (Polletta et al. 2007; gray solid line) as a guide line are indicated. The red dashed line represents the coronal emission expected from a RQ AGN with the same L_{2500 Å} of PSO J0309+27 according to Just et al. (2007) relation; the orange shaded area is the 1σ uncertainty on this estimate.