Extended, Dusty Star Formation Fueled by a Residual Cooling Flow in the
  Cluster of Galaxies Sersic 159-03
  While the cooling of the hot intra-cluster medium (ICM) in the cores of
galaxy clusters is mostly counteracted by heating from the central active
galactic nucleus (AGN), the balance is not perfect. This can lead to residual
cooling flows and low-level star formation, the physics of which is not well
understood. Here we present a detailed study of the residual cooling flow in
the center of the low mass galaxy cluster Sersic 159-03 (A S1101) using
far-ultraviolet imaging from the Hubble Space Telescope and far-infrared (FIR)
spectroscopy and photometry from the Herschel space observatory, along with a
wealth of archival data. We detect extended emission at UV, FIR, and [CII],
indicating a star formation rate of ~1-3 Msun/yr, depending on the indicator
and assumptions made. The most recently formed stars appear spatially
coincident with the lowest entropy ICM. We speculate that this low-entropy gas
has been displaced by the central AGN ~7.5 kpc north of the cD galaxy. These
data demonstrate that the displacement of the cooling core from the direct
vicinity of the central AGN can temporarily break the feedback cycle and lead
to cooling and star formation that is offset from the center of the galaxy. We
find an abundance (~10^7 Msun) of cold (20K) dust in the center of the cluster
and a second FIR peak ~30kpc to the north of the central galaxy. If confirmed
to be associated with the cooling filaments, this would be the most extended
complex of dust yet found in a cool core cluster.
