Luminosities of Radio-Loud Active Galaxies

Abstract.

We investigate the host galaxy luminosities of three different samples of radio loud active nuclei at z<0.5 including BL Lac Objects (BLLs), Radio Loud Quasars (RLQs) and Radio Galaxies (FRs). The data have been extracted from images obtained with HST (for BLLs and RLQs) and with the ESO-2.2m and NOT telescopes (for RGs) All sources are well resolved and their host galaxies are luminous bulge dominated systems. After a homogeneous treatment of the data we find that the host galaxy average absolute magnitude R are: < M _R > _RLQ = -24.3, < M _R > _BLL = -23.7, < M _R > _FRI = -24.1, < M _R > _FRII = -23.6. Host of RLQ are $\sim$ 0.5 mag brighter than those of BLLs which are intermediate between RG of FR I and FR II type. These galaxy luminosities are used to evaluate the central black hole masses from the M _BH -L _bulge relation found for nearby spheroidal galaxies. Finally we construct the Host Galaxy Luminosity Function for the different classes of AGN and compare its shape with that of elliptical galaxies.