The Atlas3D project - XIX. The hot-gas content of early-type galaxies: fast versus slow rotators. (arXiv:1301.2589v1 [astro-ph.GA])

The Atlas3D project - XIX. The hot-gas content of early-type galaxies: fast versus slow rotators. (arXiv:1301.2589v1 [astro-ph.GA]):
For early-type galaxies, the ability to sustain a corona of hot, X-ray
emitting gas could have played a key role in quenching their star-formation
history. Yet, it is still unclear what drives the precise amount of hot gas
around these galaxies. By combining photometric and spectroscopic measurements
for the early-type galaxies observed during the Atlas3D integral-field survey
with measurements of their X-ray luminosity based on X-ray data of both low and
high spatial resolution we conclude that the hot-gas content of early-type
galaxies can depend on their dynamical structure. Specifically, whereas slow
rotators generally have X-ray halos with luminosity L_X,gas and temperature T
values that are in line with what is expected if the hot-gas emission is
sustained by the thermalisaton of the kinetic energy carried by the
stellar-mass loss material, fast rotators tend to display L_X,gas values that
fall consistently below the prediction of this model, with similar T values
that do not scale with the stellar kinetic energy as observed in the case of
slow rotators. Considering that fast rotators are likely to be intrinsically
flatter than slow rotators, and that the few L_X,gas-deficient slow rotators
also happen to be relatively flat, the observed L_X,gas deficiency in these
objects would support the hypothesis whereby flatter galaxies have a harder
time in retaining their hot gas. We discuss the implications that a different
hot-gas content could have on the fate of both acquired and internally-produced
gaseous material, considering in particular how the L_X,gas deficiency of fast
rotators would make them more capable to recycle the stellar-mass loss material
into new stars than slow rotators. This is consistent with the finding that
molecular gas and young stars are detected only in fast rotators in the Atlas3D
sample, and that fast rotators tend to dustier than slow rotators. [Abridged]