A conspicuous tangential alignment of galaxies in a STIS Parallel Shear   Survey field: A new dark-lens candidate ?
  We report the serendipituous discovery of a conspicuous alignment of galaxies in a field obtained through the STIS Parallel Shear Survey. This project collects randomly distributed 50'' x 50'' fields to investigate the cosmic shear effect on this scale. Analyzing the parallel observations having the Seyfert galaxy NGC625 as primary target, we recognized over the whole field of view a strong apparent tangential alignment of galaxy ellipticities towards the image center. The field shows several arclet-like features typical for images of massive galaxy clusters, but no obvious over-density of bright foreground galaxies. We also find a multiple image candidate. On the basis of the possible strong and weak lensing effect within the data, we discuss whether this could be compatible with a massive halo with no clear optical counterpart. 
J.-M. Miralles, T. Erben, H. Haemmerle, P. Schneider, R.A.E. Fosbury,   W. Freudling, N. Pirzkal, B. Jain, S.D.M. White