Distribution of water in the G327.3-0.6 massive star-forming region

Abstract

We aim at characterizing the large-scale distribution of H2O in G327.3-0.6, a massive star-forming region made of individual objects in different evolutionary phases. We investigate variations of H2O abundance as function of evolution. We present Herschel continuum maps at 89 and 179 $\mu$m of the whole region and an APEX map at 350 μm of the IRDC. New spectral HIFI maps toward the IRDC region covering low-energy H2O lines at 987 and 1113 GHz are also presented and combined with HIFI pointed observations of the G327 hot core. We infer the physical properties of the gas through optical depth analysis and radiative transfer modeling. The continuum emission at 89 and 179 μm follows the thermal continuum emission at longer wavelengths, with a peak at the position of the hot core, a secondary peak in the Hii region, and an arch-like layer of hot gas west of the Hii region. The same morphology is observed in the 1113 GHz line, in absorption toward all dust condensations. Optical depths of ~80 and 15 are estimated and correspond to column densities of 10^15 and 2 10^14 cm-2, for the hot core and IRDC position. These values indicate an H2O to H2 ratio of 3 10^-8 toward the hot core; the abundance of H2O does not change along the IRDC with values of some 10^-8. Infall (over ~ 20") is detected toward the hot core position with a rate of 1-1.3 10^-2 M_sun /yr, high enough to overcome the radiation pressure due to the stellar luminosity. The source structure of the hot core region is complex, with a cold outer gas envelope in expansion, situated between the outflow and the observer, extending over 0.32 pc. The outflow is seen face-on and centered away from the hot core. The distribution of H2O along the IRDC is roughly constant with an abundance peak in the more evolved object. These water abundances are in agreement with previous studies in other massive objects and chemical models.

Accepted by A&A

References in corpus (14)

• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Infall through the evolution of high-mass star-forming clumps
• ATLASGAL - Kinematic distances and the dense gas mass distribution of the inner Galaxy
• Outflows, infall and evolution of a sample of embedded low-mass protostars. The William Herschel Line Legacy (WILL) survey
• Herschel Far-Infrared Spectral-mapping of Orion BN/KL Outflows: Spatial distribution of excited CO, H2O, OH, O and C+ in shocked gas
• The CDF Archive: Herschel PACS and SPIRE Spectroscopic Data Pipeline and Products for Protostars and Young Stellar Objects
• BoA: a versatile software for bolometer data reduction
• Water distribution in shocked regions of the NGC1333-IRAS4A protostellar outflow
• Revealing the environs of the remarkable southern hot core G327.3-0.6
• The Circumstellar Environment of High-Mass Protostellar Objects: IV. C17O Observations and Depletion
• Evidence of triggered star formation in G327.3-0.6. Dust-continuum mapping of an infrared dark cloud with P-ArTéMiS
• Water emission from the high-mass star-forming region IRAS 17233-3606. High water abundances at high velocities
• The Herschel-HIFI view of mid-IR quiet massive protostellar objects
• Structure and kinematics of the clouds surrounding the Galactic mini-starburst W43 MM1

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