Molecular gas along the old radio jets of the cluster-central type 2
  quasar IRAS 09104+4109
  We present Northern Extended Millimeter Array (NOEMA) CO(2-1) maps of the
z=0.4418 cluster-central QSO IRAS 09104+4109, which trace ~4.5x10^10 Msol of
molecular gas in and around the galaxy. As in many low redshift cool core
clusters, the molecular gas is located in a series of clumps extending along
the old radio jets and lobes. It has a relatively low velocity dispersion (336
[+39,-35] km/s FWHM) and shows no velocity gradients indicative of outflow or
infall. Roughly half the gas is located in a central clump on the northeast
side of the galaxy, overlapping a bright ionized gas filament and a spur of
excess X-ray emission, suggesting that this is a location of rapid cooling. The
molecular gas is unusually extended, out to ~55 kpc radius, comparable to the
scale of the filamentary nebula in the Perseus cluster, despite the much higher
redshift of this system. The extent falls within the thermal instability radius
of the intracluster medium (ICM), with t_cool/t_ff<25 and t_cool}/t_eddy~1
within ~70 kpc. Continuum measurements at 159.9 GHz from NOEMA and 850 micron
from the JCMT SCUBA-2 show excess far infrared emission, which we interpret as
free-free emission arising from the ongoing starburst. These observations
suggest that ICM cooling is not strongly affected by the buried QSO, and that
cooling from the ICM can build gas reservoirs sufficient to fuel quasar-mode
activity and drive the reorientation of the central AGN.
