13.2.2. Elliptical Galaxies

Weak compact radio sources are frequently found in the nuclei of elliptical galaxies, particularly those with bright emission-line nuclei and those in which 21-cm observations show the presence of significant amounts of HI. These are high-surface-brightness compact sources which are frequently variable on time scales of months to years. When examined with high angular resolution, the weak radio nuclei typically show the same characteristic asymmetric core jet structure which is observed in the nuclei of the more powerful radio galaxies and quasars (e.g., Jones et al. 1984, Wrobel et al. 1985). Often there is also large-scale structure on a scale of a kiloparsec to a few hundred kiloparsecs comparable to that found in the powerful radio sources (e.g., Wrobel and Heeschen 1984).