The high velocity outflow in NGC6334I

Abstract

We observed the high velocity outflow originating from NGC6334I in several CO transitions with the APEX telescope, with the goal of deriving the physical parameters of the gas. Using an LVG analysis, we studied line ratios between the CO(3-2), CO(4-3), and CO(7-6) data as a function of the density and of the kinetic temperature of the gas. An upper limit on the CO column density is derived by comparison with 13CO data. We constrained the temperature to be higher than 50 K and the H_2 density to values higher than n~10^4 cm^{-3} towards the peak position in the red lobe, while T>15 K and n>10^3 cm^{-3} are derived towards the peak position in the blue lobe. The physical parameters of the outflow, its mass and its energetics, have been computed using the temperatures derived from this analysis. We conclude that high kinetic temperatures are present in the outflow and traced by high excitation CO lines. Observations of high-J CO lines are thus needed to infer reliable values of the kinetic temperatures and of the other physical parameters in outflows.

APEX A&A special issue, accepted

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• Molecular line survey of the high-mass star-forming region NGC 6334I with Herschel/HIFI and the SMA
• The Massive Protostellar Cluster NGC6334I at 220 AU Resolution: Discovery of Further Multiplicity, Diversity and a Hot Multi-Core
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• The extraordinary outburst in the massive protostellar system NGC6334I-MM1: Flaring of the water masers in a north-south bipolar outflow driven by MM1B
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• ATCA 3mm observations of NGC6334I and I(N): dense cores, outflows and an UCHII region
• Impacts of pure shocks in the BHR71 bipolar outflow
• A survey of SiO 5-4 emission towards outflows from massive young stellar objects
• Extremely high velocity gas from the massive YSOs in IRAS 17233-3606
• High mass star formation in the IRAS 17233-3606 region: a new nearby and bright hot core in the southern sky
• Odin observations of water in molecular outflows and shocks
• Ionization toward the high-mass star-forming region NGC 6334 I
• Herschel/HIFI observations of spectrally resolved methylidyne signatures toward the high-mass star-forming core NGC6334I
• Mopra line survey mapping of NGC6334I and I(N) at 3mm
• The interaction of young massive stars with their environment: A millimeter and submillimeter line study of NGC6334 FIR II
• High Velocity Compact Clouds in the Sagittarius C Region
• A Catalog of CH_3OH 7_0-6_1 A^+ Maser Sources in Massive Star-Forming Regions. II. Masers in NGC 6334F, G8.67-0.36, and M17
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• The Extraordinary Outburst in the Massive Protostellar System NGC6334I-MM1: Spatio-kinematics of Water Masers during a Contemporaneous Flare Event
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