MusE GAs FLOw and Wind (MEGAFLOW) V. The dust/metallicity-anisotropy of
  the Circum-Galactic Medium
  We investigate whether the dust content of the circum-galactic medium (CGM)
depends on the location of the quasar sightline with respect to the galaxy
major-axis using 13 galaxy-MgII absorber pairs (9 - 81 kpc distance) from the
MusE GAs FLOw and Wind (MEGAFLOW) survey at 0.4 < z < 1.4. The dust content of
the CGM is obtained from [Zn/Fe] using Ultraviolet and Visual Echelle
Spectrograph (UVES) data. When a direct measurement of [Zn/Fe] is unavailable,
we estimate the dust depletion from a method which consists in solving for the
depletion from multiple singly ionized ions (e.g. MnII, CrII, ZnII) since each
ion depletes on dust grains at different rates. We find a positive correlation
between the azimuthal angle and [Zn/Fe] with a Pearson's r = 0.70 +/- 0.14. The
sightlines along the major axis show [Zn/Fe] < 0.5, whereas the [Zn/Fe] is >
0.8 along the minor axis. These results suggest that the CGM along the minor
axis is on average more metal enriched (by ~ 1 dex) than the gas located along
the major axis of galaxies provided that dust depletion is a proxy for
metallicity. This anisotropic distribution is consistent with recent results on
outflow and accretion in hydro-dynamical simulations.
