X-ray Scaling Relations of core and coreless E and S0 Galaxies
  We have re-examined the two X-ray scaling relations of early-type galaxies
(ETGs), Lx - LK and Lx - T, using 61 ATLAS3D E and S0 galaxies observed with
Chandra. The larger sample allows us to investigate the effect of structural
and dynamical properties of ETGs in these relations. Using the sub-sample of
genuine E galaxies with central surface brightness cores, slow stellar
rotations and old stellar populations, we find that the scatter of the
correlations is strongly reduced, yielding an extremely tight relation. For the
gas-rich galaxies in this sample, this relation is consistent with recent
simulations. However, the tight Lx - T relation of genuine E galaxies extends
down into the Lx 1038 erg s-1 range, where simulations predict the gas to be in
outflow/wind state. The observed correlation may suggest the presence of small
bound hot halos even in this low luminosity range. At the high luminosity end,
the Lx - T correlation of core elliptical galaxies is similar to that found in
samples of cD galaxies and groups, but shifted down toward lower Lx. In
particular cDs have an order of magnitude higher Lx than core galaxies for the
same LK and T. We suggest that enhanced cooling in cDs could lower T to the
range observed in giant Es; this conclusion is supported by the presence of
extended cold gas in several cDs. Instead, in the sub-sample of coreless ETGs,
Lx and T are not correlated, suggesting that both the energy input from star
formation and the effect of galactic rotation and flattening may disrupt the
hot ISM.
