IRAS16547-4247: A New Candidate of a Protocluster Unveiled with ALMA
  We present the results of continuum and 12CO(3-2) and CH3OH(7-6) line
observations of IRAS16547-4247 made with the Atacama Large
Millimeter/submillimeter Array (ALMA) at an angular resolution of ~0.5". The
12CO(3-2) emission shows two high-velocity outflows whose driving sources are
located within the dust continuum peak. The alignment of these outflows do not
coincide with that of the wide-angle, large scale, bipolar outflow detected
with APEX in previous studies. The CH3OH(7-6) line emission traces an hourglass
structure associated with the cavity walls created by the outflow lobes. Taking
into account our results together with the position of the H2O and class I
CH3OH maser clusters, we discuss two possible scenarios that can explain the
hourglass structure observed in IRAS16547-4247: (1) precession of a biconical
jet, (2) multiple, or at least two, driving sources powering intersecting
outflows. Combining the available evidence, namely, the presence of two
cross-aligned bipolar outflows and two different H2O maser groups, we suggest
that IRAS16547-4247 represents an early formation phase of a protocluster.
