Revealing a detailed mass distribution of a high-density core
  MC27/L1521F in Taurus with ALMA
  We present the results of ALMA observations of dust continuum emission and
molecular rotational lines toward a dense core MC27 (aka L1521F) in Taurus,
which is considered to be at a very early stage of star formation. The detailed
column density distribution on size scales from a few tens AU to ~10,000 AU
scale are revealed by combining the ALMA (12 m array + 7 m array) data with the
published/unpublished single-dish data. The high angular resolution
observations at 0.87 mm with a synthesized beam size of ~0."74 x 0."32 reveal
that a protostellar source, MMS-1, is not spatially resolved and lacks
associated gas emission, while a starless high-density core, MMS-2, has
substructures both in dust and molecular emission. The averaged radial column
density distribution of the inner part of MC27/L1521F (r $\lesssim$ 3000 AU) is
N(H2) ~r$^{-0.4}$, clearly flatter than that of the outer part, ~r$^{-1.0}$.
The complex velocity/spatial structure obtained with previous ALMA observations
is located inside the inner flatter region, which may reflect the dynamical
status of the dense core.
