Search of the gravitational lens candidates


The aim of our work Elyiv et al. (2013) was to identify gravitational lens candidates among 5500 optical counterparts of the X-ray point-like sources in the medium-deep∼ 11 deg2 XMM -LSS survey. We have visually inspected the optical counterparts of each QSOs/AGN using CFHTLS T006 images. We have selected compact pairs and groups of sources which could be multiply imaged QSO/AGN. We have measured the colours and characterized the morphological types of the selected sources using the multiple point spread function fitting technique.

Optical CFHTLS image of the best three gravitational lens candidates in XMM-LSS field.
Fig. 13. Optical CFHTLS image of the best three gravitational lens candidates in XMM-LSS field. (Fig. 1 in Elyiv et al. 2013).

We found three good gravitational lens candidates: J021511.4− 034306, J022234.3− 031616 and J022607.0− 040301 (fig. 13) which consist of pairs of point-like sources having similar colours. On the basis of a colour–colour diagram and X-ray properties we could verify that all these sources are good QSO/AGN candidates rather than stars. Additional secondary gravitational lens candidates are also reported.