Description
We wish to exploit the unmatched combination of high angular resolution, high sensitivity, high-imaging fidelity, and spectral coverage provided by ALMA to shed light on the complex kinematics of the innermost central regions of HH212 protostellar system. We mapped the inner 10" (4500AU) of the HH212 system at ~0.5" resolution in several molecular tracers and in the 850um dust continuum using the ALMA interferometer in band 7 in the extended configuration of the Early Science Cycle 0 operations. Within a single ALMA spectral set-up, we simultaneously identify all the crucial ingredients known to be involved in the star formation recipe: (i) the fast, collimated bipolar SiO jet driven by the protostar; (ii) the large-scale swept-up CO outflow; (iii) the flattened rotating and infalling envelope, with bipolar cavities carved by the outflow (in C^17^O(3-2)); and (iv) a rotating wide-angle flow that fills the cavities and surrounds the axial jet (in C^34^S(7-6)). In addition, the compact high-velocity C^17^O emission (+/-1.9-3.5km/s from systemic) shows a velocity gradient along the equatorial plane consistent with a rotating disk of ~0.2"=90AU around a ~0.3+/-0.1M_{sun}_ source. The rotating disk is possibly Keplerian. HH212 is the third Class 0 protostar with possible signatures of a Keplerian disk of radius >=30AU. The warped geometry in our CS data suggests that this large Keplerian disk might result from misaligned magnetic and rotation axes during the collapse phase. The wide-angle CS flow suggests that disk winds may be present in this source.
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