The first ALMA view of IRAS 16293-2422: Direct detection of infall onto
  source B and high-resolution kinematics of source A
  Aims: We focus on the kinematical properties of a proto-binary to study the
infall and rotation of gas towards its two protostellar components. Methods: We
present ALMA Science Verification observations with high-spectral resolution of
IRAS 16293-2422 at 220.2 GHz. The wealth of molecular lines in this source and
the very high spectral resolution offered by ALMA allow us to study the gas
kinematics with unprecedented detail. Results: We present the first detection
of an inverse P-Cygni profile towards source B in the three brightest lines.
The line profiles are fitted with a simple two-layer model to derive an infall
rate of 4.5x10^-5 Msun/yr. This infall detection would rule-out the previously
suggested possibility that source B is a T Tauri star. A position velocity
diagram for source A shows evidence for rotation with an axis close to the
line-of-sight.
