Abstract

SF-05-0010

Multiple scales of view for outflow driven by a high-mass young stellar object, G25.82?W1

Jungha Kim, Mikyoung Kim, Tomoya Hirota, Kee-Tae Kim

We investigate the extended outflow from G25.82--W1, one of the members of a high-mass protocluster, G25.82-0.17, to study the star-forming environment of G25.82?W1. For outflow identification, CO 2-1 data was obtained with the Atacama Large Millimeter/submillimeter Array. 
  Including the outflowing gas from G25.82?W1, various spatial and spectral outflows are identified: 1) an extended N1?S1 CO outflow, driven by a high-mass young stellar object (HM-YSO), G25.82?W1, 2) an elongated SE?NW outflow powered by G25.82?W2, 3) a compact and curved N2?S2 CO outflow from G25.82?E, and 4) a pair of knotty lobes having the center in G25.82?W.
 Furthermore, the innermost interior of N1--S1 CO outflow traced by the 22 GHz H2O maser shows a complicated spatial and velocity structure within 2 " from the launching point of that.  
  An accurate distance, d=4.5 kpc, is used, derived by measuring the annual parallax of H2O masers to calculate the properties of N1?S1 CO outflow. Outflow rate and force are comparable with those of outflows from other HM-YSOs. The physical properties of N1?S1 CO outflow are on the trend connecting low and high-mass regimes, supporting star-forming mode in G25.82?W1 is likely a scaled-up version of low-mass star formation.