High-resolution ammonia mapping of the very young protostellar core
  Chamaeleon-MMS1
  Cha-MMS1 was mapped in the NH_3(1,1) line and the 1.2 cm continuum using the
Australia Telescope Compact Array, ATCA. The angular resolution of the ATCA
observations is 7'' (~ 1000 AU), and the velocity resolution is 50 m s^{-1}.
The core was also mapped with the 64-m Parkes telesope in the NH_3(1,1) and
(2,2) lines. Observations from Herschel Space Observatory and Spitzer Space
telescope were used to help interpretation. A compact high column density core
with a steep velocity gradient is detected in ammonia, with a fractional
ammonia abundance compatible with determinations towards other dense cores. The
direction of the velocity gradient agrees with previous single-dish
observations, and the overall velocity distribution can be interpreted as
rotation. The rotation axis goes through the position of a compact far-infrared
source detected by Spitzer and Herschel. The specific angular momentum of the
core is typical for protostellar envelopes. A string of 1.2 cm continuum
sources is tentatively detected near the rotation axis. The ammonia spectra
suggest the presence of warm embedded gas in its vicinity. An hourglass-shaped
structure is seen in ammonia at the cloud's average LSR velocity, also aligned
with the rotation axis. Although this structure resembles a pair of outflow
lobes the ammonia spectra show no indications of shocked gas. The observed
ammonia structure mainly delineates the inner envelope around the central
source. The velocity gradient is likely to originate in the angular momentum of
the contracting core, although influence of the outflow from the neighbouring
young star IRS4 is possibly visible on one side of the core. The tentative
continuum detection and the indications of a warm background component near the
rotation axis suggest that the core contains a deeply embedded outflow which
may have been missed in previous single-dish CO surveys owing to beam dilution.
