The radio and optical properties of the BL Lac object PKS 0521-36.

The radio source PKS 0521-36 has an optically variable continuum which has resulted in its classification as a BL Lac object. The spectrum does, however, contain diluted stellar absorption features and weak emission lines, which agree to give a redshift of 0.055. From the nature of the emission spectrum it is probable that the galaxy contains at least 100,000 solar masses of ionized gas. Radio observations with the VLA and an optical photograph are presented, both of which reveal the presence of extended structure, a resolved radio source of undertermined nature, and an optical jet. These two different extended structures are not spatially coincident.