ALMA observations of massive molecular gas reservoirs in dusty
  early-type galaxies
  Unresolved gas and dust observations show a surprising diversity in the
amount of interstellar matter in early-type galaxies. Using ALMA observations
we resolve the ISM in z$\sim$0.05 early-type galaxies. From a large sample of
early-type galaxies detected in the Herschel Astrophysical Terahertz Large Area
Survey (H-ATLAS) we selected five of the dustiest cases, with dust masses
M$_d\sim$several$\times10^7$M$_\odot$, with the aim of mapping their
submillimetre continuum and $^{12}$CO(2-1) line emission distributions. These
observations reveal molecular gas disks. There is a lack of associated,
extended continuum emission in these ALMA observations, most likely because it
is resolved out or surface brightness limited, if the dust distribution is as
extended as the CO gas. However, two galaxies have central continuum ALMA
detections. An additional, slightly offset, continuum source is revealed in one
case, which may have contributed to confusion in the Herschel fluxes.
Serendipitous continuum detections further away in the ALMA field are found in
another case. Large and massive rotating molecular gas disks are mapped in
three of our targets, reaching a few$\times10^{9}$M$_\odot$. One of these shows
evidence of kinematic deviations from a pure rotating disc. The fields of our
two remaining targets contain only smaller, weak CO sources, slightly offset
from the optical galaxy centres. These may be companion galaxies seen in ALMA
observations, or background objects. These heterogeneous findings in a small
sample of dusty early-type galaxies reveal the need for more such high spatial
resolution studies, to understand statistically how dust and gas are related in
early-type galaxies.
