B0712+472: a new radio four-image gravitational lens
Muxlow, T. W. B.; Pearson, T. J.; Bremer, M.; Blandford, R. D.; Fassnacht, C. D.; Readhead, A. C. S.; Miley, G. K.; Jackson, N.; Nair, S.; Browne, I. W. A.; Wilkinson, P. N.; de Bruyn, A. G.; Koopmans, L.; Snellen, I.; Schilizzi, R. T.; Myers, S.; Womble, D. S.
United Kingdom, Netherlands, United States
Abstract
A new four-image gravitational lens system, B0712+472, has been discovered during the Cosmic Lens All-Sky Survey. This system consists of four flat-spectrum radio images that are also seen on a Hubble Space Telescope (HST) image, together with the lensing galaxy. We present MERLIN, VLA and VLBA maps and WHT spectra of the system as well as the HST images. The light distribution of the lensing galaxy is highly elongated and so too is the mass distribution deduced from modelling. We suggest a redshift of ~1.33 for the lensed object; the lens redshift will require further investigation. The discovery of this new system further increases the ratio of four-image to two-image lens systems currently known, exacerbating problems of required ellipticity of matter distributions in lensing galaxies.