Stellar masses, metallicity gradients and suppressed star formation
  revealed in a new sample of absorption selected galaxies
  Context. Absorbing galaxies are selected via the detection of characteristic
absorption lines which their gas-rich media imprint in the spectra of distant
light-beacons. The proximity of the typically faint foreground absorbing
galaxies to bright background sources makes it challenging to robustly identify
these in emission, and hence to characterise their relation to the general
galaxy population. Aims. We search for emission to confirm and characterise ten
galaxies hosting damped, metal-rich quasar absorbers at redshift z < 1.
Methods. We identify the absorbing galaxies by matching spectroscopic
absorption -and emission redshifts and from projected separations. Combining
emission-line diagnostics with existing absorption spectroscopy and photometry
of quasar-fields hosting metal-rich, damped absorbers, we compare our new
detections with reference samples and place them on scaling relations. Results.
We spectroscopically confirm seven galaxies harbouring damped absorbers (a 70%
success-rate). Our results conform to the emerging picture that neutral gas on
scales of tens of kpc in galaxies is what causes the characteristic Hi
absorption. Our key results are: (I) Absorbing galaxies with $\log _{10}
[M_\star ~(M_\odot)] \gtrsim 10$ have star formation rates that are lower than
predicted for the main sequence of star formation. (II) The distribution of
impact parameter with Hi column density and with absorption-metallicity for
absorbing galaxies at $z\sim 2-3$ extends to $z\sim 0.7$ and to lower Hi column
densities. (III) A robust mean metallicity gradient of $\langle \Gamma \rangle
= 0.022 \pm 0.001~[dex~kpc^{-1}]$. (IV) By correcting absorption metallicities
for $\langle \Gamma \rangle$ and imposing a truncation-radius at
$12~\mathrm{kpc}$, absorbing galaxies fall on top of predicted mass-metallicity
relations, with a statistically significant decrease in scatter.
