Deep CCD images of 2345+007. Lensing by dark matter.

Deep CCD images of the lensed QS0 2345+007 taken in the blue, red, and infrared show no galaxy between the QS0 images to J=25.5, R=26.5, and I=25th mag. There are a few 23.8 I mag galaxies within 10 arcsec of the QS0. Even if one of these field galaxies was near the line-of-sight to the QS0 and had a velocity dispersion less than 900 km/sec, there must be other objects of very high M/L assisting the lensing. Two absorption line systems at z=1.5, separated by 1000 km/sec, are seen in the QS0 images. We would have detected galaxies at z=1.5, in the QS0 vicinity. This is the strongest case, among the six confirmed lensed QS0s, for lensing by dark compact objects.