A study of the circum-galactic medium at z ~ 0.6 using DLA-galaxies
  We present the study of a sample of nine QSO fields, with damped-Ly-alpha
(DLA) or sub-DLA systems at z~0.6, observed with the X-Shooter spectrograph at
the Very Large Telescope. By suitably positioning the X-Shooter slit based on
high spatial resolution images of HST/ACS we are able to detect absorbing
galaxies in 7 out of 9 fields (~ 78\% success rate) at impact parameters from
10 to 30 kpc. In 5 out of 7 fields the absorbing galaxies are confirmed via
detection of multiple emission lines at the redshift of DLAs where only 1 out
of 5 also emits a faint continuum. In 2 out of these 5 fields we detect a
second galaxy at the DLA redshift. Extinction corrected star formation rates
(SFR) of these DLA-galaxies, estimated using their H-alpha fluxes, are in the
range 0.3-6.7 M_sun yr^-1. The emission metallicities of these five
DLA-galaxies are estimated to be from 0.2 to 0.9 Z_sun. Based on the Voigt
profile fits to absorption lines we find the metallicity of the absorbing
neutral gas to be in a range of 0.05--0.6 Z_sun. The two remaining DLA-galaxies
are quiescent galaxies with SFR < 0.4 M_sun yr^-1 (3-sigma) presenting
continuum emission but weak or no emission lines. Using X-Shooter spectrum we
estimate i-band absolute magnitude of -19.5+/-0.2 for both these DLA-galaxies
that indicates they are sub-L* galaxies. Comparing our results with that of
other surveys in the literature we find a possible redshift evolution of the
SFR of DLA-galaxies.
