X-shooter Observations of the Gravitational Lens System CASSOWARY 5
  We confirm an eighth gravitational lens system in the CASSOWARY catalogue.
Exploratory observations with the X-shooter spectrograph on the VLT show the
system CSWA5 to consist of at least three images of a blue star-forming galaxy
at z = 1.0686, lensed by an apparent foreground group of red galaxies one of
which is at z = 0.3877. The lensed galaxy exhibits a rich spectrum with broad
interstellar absorption lines and a wealth of nebular emission lines.
Preliminary analysis of these features shows the galaxy to be young, with an
age of 25-50 Myr. With a star-formation rate of approximately 20 solar
masses/yr, the galaxy has already assembled a stellar mass of 3 x 10^9 solar
masses and reached half-solar metallicity. Its blue spectral energy
distribution and Balmer line ratios suggest negligible internal dust
extinction. A more in-depth analysis of the properties of this system is
currently hampered by the lack of a viable lensing model. However, it is
already clear that CSWA5 shares many of its physical characteristics with the
general population of UV-selected galaxies at redshifts z = 1-3, motivating
further study of both the source and the foreground mass concentration
responsible for the gravitational lensing.
