Microstructure and kinematics of H2O masers in the massive star forming region IRAS 06061+2151

Abstract

We have made multi-epoch VLBI observations of H2O maser emission in the massive star forming region IRAS 06061+2151 with the Japanese VLBI network (JVN) from 2005 May to 2007 October. The detected maser features are distributed within an 1\arcsec$\times$1\arcsec (2000 au$\times$2000 au at the source position) around the ultra-compact H {\small\bf II} region seen in radio continuum emission. Their bipolar morphology and expanding motion traced through their relative proper motions indicate that they are excited by an energetic bipolar outflow. Our three-dimensional model fitting has shown that the maser kinematical structure in IRAS 06061+2151 is able to be explained by a biconical outflow with a large opening angle ($>$ 50\degr). The position angle of the flow major axis coincides very well with that of the large scale jet seen in 2.1$\:μ\rmn{m}$ hydrogen emission. This maser geometry indicates the existence of dual structures composed of a collimated jet and a less collimated massive molecular flow. We have also detected a large velocity gradient in the southern maser group. This can be explained by a very small (on a scale of several tens of au) and clumpy (the density contrast by an order of magnitude or more) structure of the parental cloud. Such a structure may be formed by strong instability of shock front or splitting of high density core.

arXiv comment14 pages, 6 figures accepted for publication in MNRAS

References in corpus (15)

• IRAS 05358+3543: Multiple outflows at the earliest stages of massive star formation
• Millimetre continuum observations of southern massive star formation regions. I. SIMBA observations of cold cores
• A SCUBA imaging survey of ultracompact HII regions: The environments of massive star formation
• VLT K-band spectroscopy of massive young stellar objects in (ultra-)compact HII regions
• The Youngest Stellar clusters Clusters associated with massive protostellar candidates
• Precursors of UCHII regions & the evolution of massive outflows
• Clustered Star Formation in W75 N
• Water Masers as Tracers of Protostellar Disks and Outflows in the Intermediate Mass Star Forming Region NGC 2071
• Kinematics of water masers in high-mass star forming regions
• Tracing the base of protostellar wind(s) towards the high-mass star forming region AFGL 5142: VLA continuum and VLBA water maser observations
• A Global Jet/Circulation Model for Young Stars
• Bigradient Phase Referencing
• From Ultracompact to Extended HII Regions. II: Cloud Gravity and Stellar Motion
• Detection of Knots and Jets in IRAS 06061+2151
• Transit flow models for low and high mass protostars

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• Intermittent maser flare around the high mass young stellar object G353.273+0.641 I: data & overview