The double QSO 2345+007 comprises two optical components separated by 7.1 arcsec, and is the most prominent `dark matter' gravitational lens candidate. Despite being known for more than a decade, optical spectroscopy and imaging have been unable to determine whether this double QSO is a binary QSO or a gravitational lens system. In this note we report a deep VLA observation of this system, yielding a map with a noise level of 8.5 muJy beam^-1. We have a 4sigma detection of a radio source within 0.4 arcsec of the optical position of the brighter A-component of the QSO, but no significant detection of any radio counterpart of the B-component. Given that the flux ratio in the optical waveband is ~3-4, the gravitational lens hypothesis for this system would predict a radio flux of image B of <~10 muJy. The non-detection of the B-component is thus consistent with, but does not prove, the lens interpretation.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- July 1996
- COSMOLOGY: OBSERVATIONS;
- DARK MATTER;
- GRAVITATIONAL LENSING;
- 5 pages, plain TeX, 1 Postscript figure included, submitted to Monthly Notices of the Royal Astronomical Society