An S-shaped arc in the galaxy cluster RX J0054.0-2823

Context. The center of the galaxy cluster RX J0054.0-2823 at z = 0.292 is a dynamically active region that includes an interacting system of three galaxies surrounded by a large halo of intra-cluster light. Aims. We report here the discovery of an S-shaped feature of total length 11 �� in the central region of this cluster and discuss its physical nature. Methods. We test the gravitational lensing assumption by doing a mass modeling of the central part of the galaxy cluster. Results. We very naturally reproduce position and form of this S-shaped feature as a gravitationally lensed background object at redshift between 0.5 and 1.0. Conclusions. 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 ∼ 24 mag arcsec −2 .