A NEW SURVEY FOR GIANT ARCS

Abstract

We report on the first results of an imaging survey to detect strong gravitational lensing targeting the richest clusters selected from the photometric data of the Sloan Digital Sky Survey (SDSS) with follow-up deep imaging observations from the Wisconsin–Indiana–Yale NOAO (WIYN) 3.5 m telescope and the University of Hawaii 88 inch telescope (UH88). The clusters are selected from an area of 8000 deg^2 using the red cluster sequence technique and span the redshift range 0.1 ≾ z ≾ 0.6, corresponding to a comoving cosmological volume of ~2 Gpc^3. Our imaging survey thus targets a volume more than an order of magnitude larger than any previous search. A total of 240 clusters were imaged of which 141 had sub-arcsecond image quality. Our survey has uncovered 16 new lensing clusters with definite giant arcs, an additional 12 systems for which the lensing interpretation is very likely, and 9 possible lenses which contain shorter arclets or candidate arcs which are less certain and will require further observations to confirm their lensing origin. Among these new systems are several of the most dramatic examples of strong gravitational lensing ever discovered, with multiple bright arcs at large angular separation. These will likely become “poster-child” gravitational lenses similar to Abell 1689 and CL0024+1654. The new lenses discovered in this survey will enable future systematic studies of the statistics of strong lensing and their implications for cosmology and our structure formation paradigm.