ALMA reveals optically thin, highly excited CO gas in the jet-driven
  winds of the galaxy IC5063
  Using CO (4-3) and (2-1) Atacama Large Millimeter Array (ALMA) data, we prove
that the molecular gas in the jet-driven winds of the galaxy IC5063 is more
highly excited than the rest of the molecular gas in the disk of the same
galaxy. On average, the CO(4-3)/CO(2-1) flux ratio is 1 for the disk and 5 for
the jet accelerated or impacted gas. Spatially-resolved maps reveal that in
regions associated with winds, the CO(4-3)/CO(2-1) flux ratio significantly
exceeds the upper limit of 4 for optically thick gas. It frequently takes
values between 5 and 11, and it occasionally further approaches the upper limit
of 16 for optically thin gas. Excitation temperatures of 30-100 K are common
for the molecules in these regions. If all of the outflowing molecular gas is
optically thin, at 30-50 K, then its mass is 2*10^6 M_sun. This lower mass
limit is an order of magnitude below the mass derived from the CO(2-1) flux in
the case of optically thick gas. Molecular winds can thus be less massive, but
more easily detectable at high z than they were previously thought to be.
