Gravitational lenses and lens candidates identified from the COSMOS field

Abstract

A complete manual search has been carried out of the list of 285 423 objects, nearly all of them galaxies, identified in the Cosmic Evolution Survey (COSMOS) field that are brighter than I = 25. Two certain and one highly probable new gravitational lenses are found, in addition to the lenses and candidate lens systems previously found by Faure et al. A further list of 112 candidate lens systems is presented. Few of these are likely to be true gravitational lens systems, most being star-forming rings or pairs of companion galaxies. It is possible to examine of order 106 objects by eye in a reasonable time, although reliable detection of lenses by such methods is likely to be possible only with high-resolution data. The loss of completeness involved in a rapid search is estimated as up to a factor of 2, depending on the morphology of the lens candidate. © 2008 RAS.