Bât A, Salle réunion 6ième étage, Observatoire de Paris
Radially Infalling Molecular Gas from a X-ray Cooling Flow
Jeremy LIM
ASIAA, Taiwan
Résumé :
Rich groups and clusters of galaxies are immersed in hot (107-108 K)
X-ray-emitting gas, which is cooling by virtue of its X-ray radiation.
In many clusters, the cooling times are so short that we should see
a flow of cool gas to the cluster center; i.e., a X-ray cooling flow.
Although predicted 30 years ago, such cooling flows have yet to be
definitively observed. Rather, in apparent contradiction with
predictions, recent X-ray spectroscopy of putative cooling-flow
clusters fail to find gas at about one-third the cluster virial
temperature. Furthermore, X-ray imaging at high angular resolutions
reveal that the X-ray gas at the centers of putative cooling-flow
clusters is usually disturbed by radio jets from the central galaxy.
These results suggest that the X-ray gas at the cluster center is
reheated thereby diminishing if not preventing a cooling flow.
In this presentation, we provide the strongest and perhaps first
definitive evidence for cool gas deposited by a X-ray cooling
flow. The observed properties of the cooling flow help to resolve
many of the current paradoxes in the riddle of X-ray cooling flows.
