GRAVITATIONAL LENS CANDIDATES IN THE E-CDFS

We report 10 lens candidates in the Extended Chandra Deep Field South from the GEMS survey. Nine of the systems are new detections and only one of the candidates is a known lens system. For the most promising five systems including the known lens system, we present results from preliminary lens mass modeling, which tests if the candidates are plausible lens systems. Photometric redshifts of the candidate lens galaxies are obtained from the COMBO-17 galaxy catalog. Stellar masses of the candidate lens galaxies within the Einstein radius are obtained by using the z-band luminosity and the V-z color-based stellar mass-to-light ratios. As expected, the lensing masses are found to be larger than the stellar masses of the candidate lens galaxies. These candidates have similar dark matter fractions as compared to lenses in SLACS and COSMOS. They also roughly follow the halo-mass-stellar-mass relation predicted by the subhalo abundance matching technique. One of the candidate lens galaxies qualifies as a luminous infrared galaxy and may not be a true lens because the arc-like feature in the system is likely to be an active region of star formation in the candidate lens galaxy. Among the five best candidates, one is a confirmed lens system, one is likely a lens system, two are less likely to be lenses, and the status of one of the candidates is ambiguous. Spectroscopic follow-up of these systems is still required to confirm lensing and/or for more accurate determination of the lens masses and mass density profiles.