Radio observations of a candidate cosmic string gravitational lens

The "twin-galaxies" field was tentatively suggested by Cowie and Hu as a candidate for gravitational lensing by a cosmic string. We present observations of the field made at λ = 20 cm with the A array of the VLA. We detect radio emission apparently associated with one galaxy of one of the pairs. The power and morphology are typical of a common class of radio sources, and there is nothing unusual about the properties of the radio emission to suggest that it is influenced by gravitational lensing or due to emission from the cosmic string itself. These observations make the lensing interpretation appear unlikely. However, in the absence of optical data of higher resolution and more precise registration of the radio and optical images, they cannot rule out all possible string lens models. We note that a straight string cannot accommodate the widely varying position angles of the pairs, and that the small dispersion in the measured image separations is unlikely in the case of a convoluted string.