The CASTLES project
is obtaining a uniform set of public domain V, I and H-band HST
images of the known gravitational lenses. The CASTLES site also
has an episodically updated data base of the known lenses and
their properties. These data are the basis for many of our analyses.
(Right) This example show the H-band image of Q0957+561, the first lens discovered back in 1979.
In addition to the two images of the quasar and the bright lens galaxy, we see large,
arcs formed by the lensed images of the quasar host galaxy. By analyzing these arcs,
we can improve on estimates of the Hubble constant based on the time delay between the
two images (Keeton et al. 2000).
(Left) Sometimes the host galaxy can be even more spectacular, as in this H-band image of
MG1131+0456. Here the host galaxy of the lensed radio source is several times brighter
than the foreground lens galaxy (Kochanek et al. 2000).
For many more pictures, go to the CASTLES page.