1400 + 162 - an extended radio source identified with a BL Lacertae object in a group of galaxies

This paper presents optical, infrared, and radio observations of the radio source 1400 + 162, which has been identified with a neutral stellar object. This source is classified as a BL Lacertae object based on the absence of broad emission features, its high degree of optical polarization, and its steep optical continuum. A weak narrow emission line is identified as the 3727-A feature of forbidden O II at z = 0.244, in agreement with the redshift of the nearest and brightest galaxy in a small adjacent group. The radio source 1400 + 162 differs from the sources associated with the majority of BL Lacertae objects in that, even at high frequencies, a significant fraction of its emission arises in extended components. The implications of the properties of 1400 + 162 for the interpretation of the physical conditions in BL Lacertae objects are briefly discussed.