Massive molecular gas flows in the Abell 1664 brightest cluster galaxy
  We report ALMA Early Science CO(1-0) and CO(3-2) observations of the
brightest cluster galaxy (BCG) in Abell 1664. The BCG contains 1.1x10^{10}
solar masses of molecular gas divided roughly equally between two distinct
velocity systems: one from -250 to +250 km/s centred on the BCG's systemic
velocity and a high velocity system blueshifted by 570 km/s with respect to the
systemic velocity. The BCG's systemic component shows a smooth velocity
gradient across the BCG center with velocity proportional to radius suggestive
of solid body rotation about the nucleus. However, the mass and velocity
structure are highly asymmetric and there is little star formation coincident
with a putative disk. It may be an inflow of gas that will settle into a disk
over several 10^8 yr. The high velocity system consists of two gas clumps, each
~2 kpc across, located to the north and southeast of the nucleus. Each has a
line of sight velocity spread of 250-300 km/s. The velocity of the gas in the
high velocity system tends to increase towards the BCG center and could signify
a massive high velocity flow onto the nucleus. However, the velocity gradient
is not smooth and these structures are also coincident with low optical-UV
surface brightness regions, which could indicate dust extinction associated
with each clump. If so, the high velocity gas would be projected in front of
the BCG and moving toward us along the line of sight in a massive outflow most
likely driven by the AGN. A merger origin is unlikely but cannot be ruled out.
