  We perform a joint-analysis of high spatial resolution molecular gas and
star-formation rate (SFR) maps in main-sequence star-forming galaxies
experiencing galactic-scale outflows of ionised gas. Our aim is to understand
the mechanism that determines which galaxies are able to launch these intense
winds. We observed CO(1-0) at 1" resolution with ALMA in 16 edge-on galaxies,
which also have 2" spatial resolution optical integral field observations from
the SAMI Galaxy Survey. Half the galaxies in the sample were previously
identified as harbouring intense and large-scale outflows of ionised gas
("outflow-types"), the rest serve as control galaxies. The dataset is
complemented by integrated CO(1-0) observations from the IRAM 30-m telescope to
probe the total molecular gas reservoirs. We find that the galaxies powering
outflows do not possess significantly different global gas fractions or
star-formation efficiencies when compared with a control sample. However, the
ALMA maps reveal that the molecular gas in the outflow-type galaxies is
distributed more centrally than in the control galaxies. For our outflow-type
objects, molecular gas and star-formation is largely confined within their
inner effective radius ($\rm r_{eff}$), whereas in the control sample the
distribution is more diffuse, extending far beyond $\rm r_{eff}$. We infer that
outflows in normal star-forming galaxies may be caused by dynamical mechanisms
that drive molecular gas into their central regions, which can result in
locally-enhanced gas surface density and star-formation.

Astrophysics of Galaxies