Spectroscopy of lensing galaxies in the GTC era

Abstract

We are using OSIRIS at the 10.4-m Gran Telescopio CANARIAS (GTC) to obtain spectra of faint galaxies close to multiply imaged quasars. We initially focused on the fields of HE 1413+117 (Cloverleaf quasar) and SDSS 1116+4118. In this contribution, we present long-slit spectroscopy of two galaxies in the southwest of the Cloverleaf, and show that one of them makes a negligible contribution to the external shear of the gravitational lens system. Spectra of the main lensing galaxy candidate in SDSS 1116+4118 are also analysed and discused. If gravitational lensing is causing the quasar image splitting, our spectra reveal that the main lens can not consist of only one dominant galaxy.