Previous abstract Next abstract
We have observed the quasar 1213+350 ($z=0.851$) as part of the Caltech--Jodrell Survey (Xu et al.~1992, BAAS, 24, 1300) at frequencies 1.6~GHz, 5~GHz, 8.4~GHz and 15~GHz. The three lower-frequency maps all show two components, separated by 37~milliarcsec, having very similar spectral indices. The 1.6~GHz and 5~GHz maps show, in addition, that each of these components comprises a compact core and a weak jet. The symmetry of the objects is such that these could be images due to gravitational lensing of the quasar. The overall spectrum flattens between 8~GHz and 15~GHz so that 15~GHz observations (which are now being analyzed) should reveal whether each of the candidate ``images'' contains a flat-spectrum compact component -- which would be strong evidence for lensing. If 1213+350 is lensed, this will be the smallest gravitational lense by a factor ten, implying a lensing mass of around $10^8 M_\odot$.
The flux-density ratio in the two ``images'' is $30:1$, so that this is a rather unlikely configuration for a lensed system, given the number of objects searched. If this is not a lensed system, then it must either be a system with two centers of activity or a system in which a compact component is observed on the side of the center of activity opposite the jet -- a unique configuration.
Whichever explanation pertains, it is clear that 1213+350 is a most unusual object which will merit much study.