The extremely high velocity outflow from the luminous young stellar object G5.89-0.39

Abstract

We have imaged the extremely high velocity outflowing gas in CO (2-1) and (3-2) associated with the shell-like ultracompact H II region G5.89-0.39 at a resolution of 3″ (corresponding to 4000AU) with the Submillimeter Array. The integrated high-velocity (≳45kms-1) CO emission reveals at least three blueshifted lobes and two redshifted lobes. These lobes belong to two outflows, one oriented N-S, the other NW-SE. The NW-SE outflow is likely identical to the previously detected Brγ outflow. Furthermore, these outflow lobes all clearly show a Hubble-like kinematic structure. For the first time, we estimate the temperature of the outflowing gas as a function of velocity with large velocity gradient calculations. Our results reveal a clear increasing trend of temperature with gas velocity. The observational features of the extremely high velocity gas associated with G5.89-0.39 qualitatively favor the jet-driven bow shock model. © 2012 The American Astronomical Society. All rights reserved.