The Atlas3D project - V. The CO Tully-Fisher relation of early-type
  galaxies
  We demonstrate here using both single-dish and interferometric observations
that CO molecules are an excellent kinematic tracer, even in high-mass
galaxies, allowing us to investigate for the first time the CO Tully-Fisher
relation of early-type galaxies. We compare the Tully-Fisher relations produced
using both single-dish and interferometric data and various inclination
estimation methods, and evaluate the use of the velocity profile shape as a
criterion for selecting galaxies in which the molecular gas extends beyond the
peak of the rotation curve. We show that the gradient and zero-point of the
best-fit relations are robust, independent of the velocity measure and
inclination used, and agree with those of relations derived using stellar
kinematics. We also show that the early-type CO Tully-Fisher (CO-TF) relation
is offset from the CO-TF of spirals by 0.98 \pm 0.22 magnitude at Ks-band, in
line with other results. The intrinsic scatter of the relation is found to be
\approx 0.4 magnitudes, similar to the level found in the spiral galaxy
population. Next generation facilities such as the Large Millimeter Telescope
(LMT) and the Atacama Large Millimeter/Sub-millimeter Array (ALMA) should allow
this technique to be used in higher-redshift systems, providing a simple new
tool to trace the mass-to-light ratio evolution of the most massive galaxies
over cosmic time.
