An Episodic Wide-angle Outflow in HH 46/47
  During star formation, the accretion disk drives fast MHD winds which usually
contain two components, a collimated jet and a radially distributed wide-angle
wind. These winds entrain the surrounding ambient gas producing molecular
outflows. We report recent observation of 12CO (2-1) emission of the HH 46/47
molecular outflow by the Atacama Large Millimeter/sub-millimeter Array, in
which we identify multiple wide-angle outflowing shell structures in both the
blue and red-shifted outflow lobes. These shells are highly coherent in
position-position-velocity space, extending to >40-50 km/s in velocity and 10^4
au in space with well defined morphology and kinematics. We suggest these
outflowing shells are the result of the entrainment of ambient gas by a series
of outbursts from an intermittent wide-angle wind. Episodic outbursts in
collimated jets are commonly observed, yet detection of a similar behavior in
wide-angle winds has been elusive. Here we show clear evidence that the
wide-angle component of the HH 46/47 protostellar outflows experiences similar
variability seen in the collimated component.
