Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A decrease of the gas exchanges between galaxies and the IGM, from 12 to
  6 billion years ago   Using a representative sample of 65 intermediate mass galaxies at z \sim 0.6,
we have inves- tigated the interplay between the main ingredients of chemical
evolution: metal abundance, gas mass, stellar mass and SFR. All quantities have
been estimated using deep spectroscopy and photometry from UV to IR and
assuming an inversion of the Schmitt-Kennicutt law for the gas fraction. Six
billion years ago, galaxies had a mean gas fraction of 32% \pm 3, i.e. twice
that of their local counterparts. Using higher redshift samples from the
literature, we explore the gas-phases and estimate the evolution of the mean
gas fraction of distant galaxies over the last 11 Gy. The gas fraction
increases linearly at the rate of 4% per Gyr from z \sim 0 to z \sim 2.2. We
also demonstrate for a statistically representative sample that < 4% of the z
\sim 0.6 galaxies are undergoing outflow events, in sharp contrast with z \sim
2.2 galaxies. The observed co-evolution of metals and gas over the past 6 Gyr
favours a scenario in which the population of intermediate mass galaxies
evolved as closed-systems, converting their own gas reservoirs into stars.

30
The categories of this paper are: q-alg
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
11
The categories of this paper are: hep-lat
2
The categories of this paper are: math
3
The categories of this paper are: physics
36
The categories of this paper are: cmp-lg
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom