An S-shaped arc in the galaxy cluster RXJ0054.0-2823
  The center of the galaxy cluster RX J0054.0-2823 at z = 0.292 is a dynamically active region which includes an interacting system of three galaxies surrounded by a large halo of intra-cluster light. We report here the discovery of an S-shaped feature of total length 11 arcsec in the central region of this cluster and discuss its physical nature. We test the gravitational lensing assumption by doing a mass modelling of the central part of the galaxy cluster. We very naturally reproduce position and form of this S-shape feature as a gravitationally lensed background object at redshift between 0.5 and 1.0. We conclude that the lensing nature is the very probable explanation for this S-shaped arc; the ultimate proof will be the spectroscopic confirmation by measuring the high redshift of this elongated feature with surface brightness V~24mag/arcsec2. 
C. Faure, E. Giraud, J. Melnick, H. Quintana, F. Selman, J. Wambsganss