The stellar mass - halo mass relation from galaxy clustering in VUDS: a
  high star formation efficiency at z~3
  The relation between the galaxy stellar mass M_star and the dark matter halo
mass M_h gives important information on the efficiency in forming stars and
assembling stellar mass in galaxies. We present the stellar mass to halo mass
ratio (SMHR) measurements at redshifts 2<z<5, obtained from the VIMOS Ultra
Deep Survey. We use halo occupation distribution (HOD) modelling of clustering
measurements on ~3000 galaxies with spectroscopic redshifts to derive the dark
matter halo mass M_h, and SED fitting over a large set of multi-wavelength data
to derive the stellar mass M_star and compute the SMHR=M_star/M_h. We find that
the SMHR ranges from 1% to 2.5% for galaxies with M_star=1.3x10^9 M_sun to
M_star=7.4x10^9 M_sun in DM halos with M_h=1.3x10^{11} M_sun} to M_h=3x10^{11}
M_sun. We derive the integrated star formation efficiency (ISFE) of these
galaxies and find that the star formation efficiency is a moderate 6-9% for
lower mass galaxies while it is relatively high at 16% for galaxies with the
median stellar mass of the sample ~7x10^9 M_sun. The lower ISFE at lower masses
may indicate that some efficient means of suppressing star formation is at work
(like SNe feedback), while the high ISFE for the average galaxy at z~3 is
indicating that these galaxies are efficiently building-up their stellar mass
at a key epoch in the mass assembly process. We further infer that the average
mass galaxy at z~3 will start experiencing star formation quenching within a
few hundred millions years.
