  Bright galaxy-galaxy strong lenses are much more powerful than lensed quasars
for measuring the mass profiles of galaxies, but until this year only a handful
have been known. Here we present five new examples, identified via the optimal
line-of-sight gravitational lens search strategy applied to luminous red
galaxies in the Sloan Digital Sky Survey (SDSS). Our survey largely complements
a similar survey by Bolton et al., who recently presented several new lenses.
The lensed background galaxies are selected from the SDSS spectra via the
presence of narrow emission line signatures, including the [OII] 3726,3729, Hb
and [OIII] 4960,5008 lines, superposed on the spectra of the bright,
intervening, deflector galaxies. Our five confirmed new systems include
deflector galaxies with redshifts z=0.17-0.28 and lensed galaxies with
redshifts z=0.47-1.18. Simulations of moderately deep (few orbits) HST-ACS
imaging of systems such as these, where the lensed source is brighter than
r~23, are presented. These demonstrate the feasibility of measuring accurately
the inner slope of the dark matter halo to within an uncertainty
sigma(gamma)~0.1, the dark matter fraction within the Einstein radius, and the
mass-to-light ratio of the stars alone, independently of dynamical
measurements. The high success rate of our search so far, >60%, and the
relatively modest observational resources necessary to confirm the
gravitational lens nature of the candidates, demonstrate that compilation of a
sample of ~100 galaxy-galaxy lenses from the SDSS is readily achievable,
opening up a rich new field in dark matter studies.
