S2COSMOS: Evolution of Gas Mass with Redshift Using Dust Emission
  We investigate the evolution of the gas mass fraction for galaxies in the
COSMOS field using submillimetre emission from dust at 850$\mu$m. We use
stacking methodologies on the 850$\mu$m S2COSMOS map to derive the gas mass
fraction of galaxies out to high redshifts, 0 <= $z$ <= 5, for galaxies with
stellar masses of $10^{9.5} < M_* (\rm M_{\odot}) < 10^{11.75}$. In comparison
to previous literature studies we extend to higher redshifts, include more
normal star-forming galaxies (on the main sequence), and also investigate the
evolution of the gas mass fraction split by star-forming and passive galaxy
populations. We find our stacking results broadly agree with scaling relations
in the literature. We find tentative evidence for a peak in the gas mass
fraction of galaxies at around $z$ ~ 2.5-3, just before the peak of the star
formation history of the Universe. We find that passive galaxies are
particularly devoid of gas, compared to the star-forming population. We find
that even at high redshifts, high stellar mass galaxies still contain
significant amounts of gas.
