The parsec-scale central components of FR I radio galaxies

Abstract

A majority of a complete sample of 3CR FR I radio galaxies show unresolved optical nuclear sources on the scales of 0.1 arcsec. These Compact Central Cores (CCC) have been interpreted as the optical counterparts of the non-thermal radio cores in these radio galaxies (Chiaberge et al. 1999). We show that the optical flux density of these CCCs is correlated with the radio core prominence. This correlation supports the argument of Chiaberge et al. that the CCC radiation is of a non-thermal synchrotron origin, which is relativistically beamed along with the radio emission.