Radio, optical and X-ray nuclei in nearby 3CRR radio galaxies

HST observations have shown that low-redshift 3CR radio galaxies often exhi bit a point-like optical component positionally coincident with the GHz-fre quency radio core. In this paper we discuss the correlation between the lum inosities of the radio, optical and X-ray cores in these objects, and argue that all three components have a common origin at the base of the relativi stic jets. In unified models, FR I radio galaxies should appear as dimmed, redshifted versions of BL Lac objects. We show that such models are consist ent with the spectral energy distributions of the radio galaxies only if th e nuclear X-ray emission in radio galaxies is inverse Compton in origin.