Most of the cool CGM of star-forming galaxies is not produced by
  supernova feedback
  The characterization of the large amount of gas residing in the galaxy halos,
the so called circumgalactic medium (CGM), is crucial to understand galaxy
evolution across cosmic time. We focus here on the the cool ($T\sim10^4$ K)
phase of this medium around star-forming galaxies in the local universe, whose
properties and dynamics are poorly understood. We developed semi-analytical
parametric models to describe the cool CGM as an outflow of gas clouds from the
central galaxy, as a result of supernova explosions in the disc (galactic
wind). The cloud motion is driven by the galaxy gravitational pull and by the
interactions with the hot ($T\sim10^6$ K) coronal gas. Through a bayesian
analysis, we compare the predictions of our models with the data of the
COS-Halos and COS-GASS surveys, which provide accurate kinematic information of
the cool CGM around more than 40 low-redshift star-forming galaxies, probing
distances up to the galaxy virial radii. Our findings clearly show that a
supernova-driven outflow model is not suitable to describe the dynamics of the
cool circumgalactic gas. Indeed, to reproduce the data, we need extreme
scenarios, with initial outflow velocities and mass loading factors that would
lead to unphysically high energy coupling from the supernovae to the gas and
with supernova efficiencies largely exceeding unity. This strongly suggests
that, since the outflows cannot reproduce most of the cool gas absorbers, the
latter are likely the result of cosmological inflow in the outer galaxy halos,
in analogy to what we have previously found for early-type galaxies.
