Cooling in the X-ray halo of the rotating, massive early-type galaxy NGC
  7049
  The relative importance of the physical processes shaping the thermodynamics
of the hot gas permeating rotating, massive early-type galaxies is expected to
be different from that in non-rotating systems. Here, we report the results of
the analysis of XMM-Newton data for the massive, lenticular galaxy NGC 7049.
The galaxy harbours a dusty disc of cool gas and is surrounded by an extended
hot X-ray emitting gaseous atmosphere with unusually high central entropy. The
hot gas in the plane of rotation of the cool dusty disc has a multi-temperature
structure, consistent with ongoing cooling. We conclude that the rotational
support of the hot gas is likely capable of altering the multiphase
condensation regardless of the $t_{\rm cool}/t_{\rm ff}$ ratio, which is here
relatively high, $\sim 40$. However, the measured ratio of cooling time and
eddy turnover time around unity ($C$-ratio $\approx 1$) implies significant
condensation, and at the same time, the constrained ratio of rotational
velocity and the velocity dispersion (turbulent Taylor number) ${\rm Ta_t} > 1$
indicates that the condensing gas should follow non-radial orbits forming a
disc instead of filaments. This is in agreement with hydrodynamical simulations
of massive rotating galaxies predicting a similarly extended multiphase disc.
