Raphael Gavazzi, Tommaso Treu, Philip J. Marshall, Florence Brault, Andrea Ruff
We study the relative alignment of mass and light in a sample of 16 massive
early-type galaxies at z=0.2-0.9 that act as strong gravitational lenses. The
sample was identified from deep multiband images obtained as part of the Canada
France Hawaii Legacy Survey (CFHTLS) as part of the Strong Lensing Legacy
Survey (SL2S). Higher resolution follow-up imaging is available for a subset of
10 systems. We construct gravitational lens models and infer total enclosed
mass, elongation, and position angle of the mass distribution. By comparison
with the observed distribution of light we infer that there is a substantial
amount of external shear $< \gamma_{\rm ext}> \approx 0.12$, arising most
likely from the environment of the SL2S lenses. In a companion paper (Ruff et
al. 2011) we combine these measurements with follow-up Keck spectroscopy to
study the evolution of the stellar and dark matter content of early-type
galaxies as a function of cosmic time.
View original:
http://arxiv.org/abs/1202.3852
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