Detection of the lensing galaxy in HE 2149-2745

Sebastian Lopez, Olaf Wucknitz, Lutz Wisotzki

Published 1998-09-14Version 1

We have obtained new BVR-band images of the gravitationally lensed QSO pair HE 2149-2745 A,B (QSO redshift z=2.033; angular separation theta_AB=1.71 arcsec), under 1 arcsec seeing conditions. Subtraction of a scaled point-spread-function reveals an extended object of angular size comparable to theta_AB, and R magnitude of 20.4 lying between and equidistant to the QSOs. The geometry of the system leads us to interpret this object as the lensing agent responsible for the double QSO images. A fit to the galaxy surface brightness profile indicates an elliptical galaxy, which is further supported by the absence of Mg II in absorption. The lensing galaxy is not detected in B and V. We discuss possible lens models for this geometry constrained by our observations and consequences for the mass and redshift of the lens.