Structure and kinematics of the clouds surrounding the Galactic
  mini-starburst W43 MM1
  Massive stars have a major influence on their environment yet their formation
is difficult to study. W43 is a highly luminous galactic massive star forming
region at a distance of 5.5 kpc and the MM1 part hosts a very massive dense
core (1000 M$_{\odot}$ within 0.05 pc). We present new Herschel HIFI maps of
the W43 MM1 region covering the main low-energy water lines at 557, 987, and
1113 GHz, their H$_2^{18}$O counterparts, and other lines such as
$^{13}$CO(10-9) and C$^{18}$O(9-8) which trace warm gas. These water lines are,
with the exception of line wings, observed in absorption. Herschel SPIRE and
JCMT 450 $\mu$m data have been used to make a model of the continuum emission
at these wavelengths. Analysis of the maps, and in particular the optical depth
maps of each line and feature, shows that a velocity gradient, possibly due to
rotation, is present in both the envelope and the protostellar core. Velocities
increase in both components from SW to NE, following the general source
orientation. While the H$_2$O lines trace essentially the cool envelope, we
show that the envelope cannot account for the H$_2^{18}$O absorption, which
traces motions close to the protostar. The core has rapid infall, 2.9 kms, as
manifested by the H$_2^{18}$O absorption features which are systematically
red-shifted with respect to the $^{13}$CO(10-9) emission line which also traces
the inner material with the same angular resolution. Some H$_2^{18}$O
absorption is detected outside the central core and thus outside the regions
expected to be above 100 K - we attribute this to warm gas associated with the
other massive dense cores in W43 MM1. Using the maps to identify absorption
from cool gas on large scales, we subtract this component to model spectra for
the inner envelope. Modeling the new spectra results in a lower water
abundance, decreased from $8 10^{-8}$ to $8 10^{-9}$ , with no change in infall
rate.
