The compact radio core of MKN 348 : evidence for directed outflow in a type 2 Seyfert galaxy.

VLBI observations of the type 2 Seyfert galaxy Mkn 348 show that the nuclear radio source consists of a core and two knots aligned along position angle 168 deg. The total size measures about 50 pc. Flux density monitoring with the WSRT over a four year interval show that the source is highly variable at 6 cm but only moderately variable at 21 cm on time scales of months, and that a new outburst began in early 1982. Structural and spectral data combined indicate the existence of an inverted-spectrum core and an optically thin jet. A low resolution synthesis map shows weak associated radio emission 20 arcsec southwest of the core. These results support the hypothesis that radio sources in both type 1 and type 2 Seyfert galaxies are powered in the same manner as radio galaxies and quasars, by jets of nonthermal material that originate in a compact energetic nucleus.