SMA 2009 Image Contest: Gone With The Wind

Magnetic fields have been a mysterious player in cloud dynamics and star formation. Only recently, their importance at scales from 100 down to 0.1 pc has been confirmed by polarimetry surveys from single-dish telescopes, e.g. CSO and JCMT. At even smaller scales, the picture has just started to be revealed by SMA. For the bulk volume of molecular cloud NGC 6334, magnetic fields uniformly orientate in the NW-SE direction, which is shown as the thick gray vector. The cloud core NGC 6334I, traced by dust thermal emission at 870 um (colored map), is shaped by the fields to elongate in NE-SW. After stars formed inside the core, however, the powerful bipolar outflows, traced by CO (3-2) emission and shown in contours, drive the fields (indicated by the orange vectors) away from their original direction in the parent cloud. It has been proposed that outflows can boost turbulent energy and help turbulence to compete with magnetic fields on dynamical importance.

  NGC 6334I

Hua-bai Li (Harvard-Smithsonian CfA), 2009

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