The bias of DLAs at z ~ 2.3: contraining stellar feedback in shallow
  potential wells
  We discuss the recent Baryon Oscillation Spectroscopic Survey measurement of
a rather high bias factor for the host galaxies/haloes of Damped Lyman-alpha
Absorbers (DLAs), in the context of our previous modelling of the physical
properties of DLAs within the $\Lambda$ cold dark matter paradigm. Joint
modelling of the column density distribution, the velocity width distribution
of associated low ionization metal absorption, and the bias parameter suggests
that DLAs are hosted by galaxies with dark matter halo masses in the range $10
< \log M_v < 12$, with a rather sharp cutoff at the lower mass end,
corresponding to virial velocities of 35 km/sec. The observed properties of
DLAs appear to suggest efficient (stellar) feedback in haloes with
masses/virial velocities below the cutoff and a large retained baryon fraction
(> 35 %) in haloes above the cutoff.
