Large-scale environment of z~5.7 CIV absorption systems I: projected
  distribution of galaxies
  Metal absorption systems are products of star formation. They are believed to
be associated with massive star forming galaxies, which have significantly
enriched their surroundings. To test this idea with high column density CIV
absorption systems at z~5.7, we study the projected distribution of galaxies
and characterise the environment of CIV systems in two independent quasar
lines-of-sight: J103027.01+052455.0 and J113717.73+354956.9. Using wide field
photometry (~80x60h$^{-1}$ comoving Mpc), we select bright (Muv(1350\AA)<-21.0
mag.) Lyman break galaxies (LBGs) at z~5.7 in a redshift slice \Delta z~0.2 and
we compare their projected distribution with z~5.7 narrow-band selected Lyman
alpha emitters (LAEs, \Delta z~0.08).
  We find that the CIV systems are located more than 10h$^{-1}$ projected
comoving Mpc from the main concentrations of LBGs and no candidate is closer
than ~5h$^{-1}$ projected comoving Mpc. In contrast, an excess of LAEs -lower
mass galaxies- is found on scales of ~10h$^{-1}$ comoving Mpc, suggesting that
LAEs are the primary candidates for the source of the CIV systems. Furthermore,
the closest object to the system in the field J1030+0524 is a faint LAE at a
projected distance of 212h$^{-1}$ physical kpc. However, this work cannot rule
out undiscovered lower mass galaxies as the origin of these absorption systems.
  We conclude that, in contrast with lower redshift examples (z<3.5), strong
CIV absorption systems at z~5.7 trace low-to-intermediate density environments
dominated by low-mass galaxies. Moreover, the excess of LAEs associated with
high levels of ionizing flux agrees with the idea that faint galaxies dominate
the ionizing photon budget at this redshift.
