IRAS 16547−4247: A New Candidate of a Protocluster Unveiled with ALMA
Chibueze, James O.
Garay Brignardello, Guido
Cita de ítem
The Astrophysical Journal Letters, 798:L33 (6pp), 2015 January 10
Artículo de publicación ISI
We present the results of continuum and 12CO(3–2) and CH3OH(7–6) line observations of IRAS 16547−4247
made with the Atacama Large Millimeter/submillimeter Array (ALMA) at an angular resolution of ∼0.
12CO(3–2) emission shows two high-velocity outflows whose driving sources are located within the dust continuum
peak. The alignment of these outflows does not coincide with that of the wide-angle, large-scale, bipolar outflow
detected with the Atacama Pathfinder Experiment 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 IRAS 16547−4247: (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 IRAS 16547−4247
represents an early formation phase of a protocluster.