High-velocity extended molecular outflow in the star-formation dominated
  luminous infrared galaxy ESO 320-G030
  We analyze new high spatial resolution (~60 pc) ALMA CO(2-1) observations of
the isolated luminous infrared galaxy ESO 320-G030 (d=48 Mpc) in combination
with ancillary HST optical and near-IR imaging as well as VLT/SINFONI near-IR
integral field spectroscopy. We detect a high-velocity (~450 km/s) spatially
resolved (size~2.5 kpc; dynamical time ~3 Myr) massive (~10^7 Msun; mass
rate~2-8 Msun/yr) molecular outflow originated in the central ~250 pc. We
observe a clumpy structure in the outflowing cold molecular gas with clump
sizes between 60 and 150 pc and masses between 10^5.5 and 10^6.4 Msun. The mass
of the clumps decreases with increasing distance, while the velocity is
approximately constant. Therefore, both the momentum and kinetic energy of the
clumps decrease outwards. In the innermost (~100 pc) part of the outflow, we
measure a hot-to-cold molecular gas ratio of 7x10^-5, which is similar to that
measured in other resolved molecular outflows. We do not find evidence of an
ionized phase in this outflow. The nuclear IR and radio properties are
compatible with strong and highly obscured star-formation (A_k ~ 4.6 mag;
SFR~15 Msun/yr). We do not find any evidence for the presence of an active
galactic nucleus. We estimate that supernova explosions in the nuclear
starburst (\nu(SN) ~ 0.2 yr^-1) can power the observed molecular outflow. The
kinetic energy and radial momentum of the cold molecular phase of the outflow
correspond to about 2% and 20%, respectively, of the supernovae output. The
cold molecular outflow velocity is lower than the escape velocity, so the gas
will likely return to the galaxy disk. The mass loading factor is ~0.1-0.5, so
the negative feedback due to this star-formation powered molecular outflow is
probably limited.
