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I will present the gravitational lens modeling for a new example of a
three-component source for which each component is quadruply imaged. The
lens is a massive galaxy member of the cluster Cl J0152.7-1357 at z ~
0.8. By taking advantage of this exceptional configuration and of the
excellent angular resolution of HST/ACS, the properties of the lens can
be measured accurately. I will discuss several macroscopic models for
the lens galaxy. In particular, I will examine a lens model in terms of
a singular isothermal sphere with external shear. The shear direction
points to the cluster central mass peak and the shear modulus gives an
approximate estimate of the large-scale mass, in agreement with the
estimates derived from X-ray and weak lensing analyses. Then, by
combining lensing analysis and spectroscopic measurements, a lower limit
to the unknown redshift of the source can be found. Finally, I will show
that the estimate of the projected mass inside the Einstein radius,
which is a function of the source distance, can be entirely ascribed to
the galaxy or partly to the galaxy and partly to the cluster, but it
does not depend on the details of the adopted model.
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