On the size of the CO-depletion radius in the IRDC G351.77-0.51

Abstract

An estimate of the degree of CO-depletion ($f_D$) provides information on the physical conditions occurring in the innermost and densest regions of molecular clouds. A key parameter in these studies is the size of the depletion radius, i.e. the radius within which the C-bearing species, and in particular CO, are largely frozen onto dust grains. A strong depletion state (i.e. $f_D>10$, as assumed in our models) is highly favoured in the innermost regions of dark clouds, where the temperature is $<20$ K and the number density of molecular hydrogen exceeds a few $\times$10${}^4$ cm${}^{-3}$. In this work, we estimate the size of the depleted region by studying the Infrared Dark Cloud (IRDC) G351.77-0.51. Continuum observations performed with the $Herschel$ $Space$ $Observatory$ and the $LArge$ $APEX$ $BOlometer$ $CAmera$, together with APEX C${}^{18}$O and C${}^{17}$O J=2$\to$1 line observations, allowed us to recover the large-scale beam- and line-of-sight-averaged depletion map of the cloud. We built a simple model to investigate the depletion in the inner regions of the clumps in the filament and the filament itself. The model suggests that the depletion radius ranges from 0.02 to 0.15 pc, comparable with the typical filament width (i.e.$\sim$0.1 pc). At these radii, the number density of H${}_2$ reaches values between 0.2 and 5.5$\times$10${}^5$ cm${}^{-3}$. These results provide information on the approximate spatial scales on which different chemical processes operate in high-mass star-forming regions and also suggest caution when using CO for kinematical studies in IRDCs.

arXiv commentaccepted to MNRAS (14 pages, 10 figures, 1 table)

References in corpus (47)

• Astropy: A Community Python Package for Astronomy
• The Astropy Project: Building an inclusive, open-science project and status of the v2.0 core package
• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• The CO-to-H2 Conversion Factor
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Characterizing interstellar filaments with Herschel in IC5146
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• Hi-GAL: the Herschel infrared Galactic Plane Survey
• Systematic Molecular Differentiation in Starless Cores
• High-Mass Proto-Stellar Candidates - II : Density structure from dust continuum and CS emission
• Probing the evolutionary status of starless cores through N2H+ and N2D+ observations
• Molecular ions in L1544. II. The ionization degree
• The WISE Catalog of Galactic HII Regions
• N2H+ and C18O Depletion in a Cold Dark Cloud
• ATLASGAL --- properties of a complete sample of Galactic clumps
• Fragmentation at the Earliest Phase of Massive Star Formation
• CO Depletion and Deuterium Fractionation in Prestellar Cores
• The Degree of CO Depletion in Pre-stellar Cores
• Survey of ortho-H2D+(1_{1,0}-1_{1,1}) in dense cloud cores
• The identification of filaments on far infrared and submillimiter images. Morphology, physical conditions and relation with star formation of filamentary structure
• ATLASGAL-selected massive clumps in the inner Galaxy: I. CO depletion and isotopic ratios
• ATLASGAL -- A Galaxy-wide sample of dense filamentary structures
• Interstellar Deuterium, Nitrogen, and Oxygen Abundances Toward GD 246, WD 2331$-$475, HZ 21, and Lan 23: Results from the FUSE Mission
• ATLASGAL-selected massive clumps in the inner Galaxy III. Dust Continuum Characterization of an Evolutionary Sample
• CO Abundance Variations in the Orion Molecular Cloud
• Mapping Large-Scale CO Depletion in a Filamentary Infrared Dark Cloud
• ATLASGAL-selected massive clumps in the inner Galaxy, II: Characterisation of different evolutionary stages and their SiO emission
• Mapping the column density and dust temperature structure of IRDCs with Herschel
• Galactic interstellar 18O/17O ratios - a radial gradient?
• ATLASGAL-selected massive clumps in the inner Galaxy: V. Temperature structure and evolution
• The Deuterium Fractionation Timescale in Dense Cloud Cores: A Parameter Space Exploration
• Galactocentric variation of the gas-to-dust ratio and its relation with metallicity
• HD depletion in starless cores
• High CO depletion in southern infrared-dark clouds
• On the kinematics of massive star forming regions: the case of IRAS 17233-3606
• Are Infrared Dark Clouds Really Quiescent?
• A Virialized Filamentary Infrared Dark Cloud
• C18O Depletion in Starless Cores in Taurus
• Deuterium fractionation and H2D+ evolution in turbulent and magnetized cloud cores
• The molecular distribution of the IRDC G351.77-0.51
• A timeline for massive star-forming regions via combined observation of o-H${}_2$D${}^{+}$ and N${}_2$D${}^{+}$
• The Circumstellar Environment of High-Mass Protostellar Objects: IV. C17O Observations and Depletion
• Fast deuterium fractionation in magnetized and turbulent filaments
• Characterising the high-mass star forming filament G351.776--0.527 with Herschel and APEX dust continuum and gas observations
• Scaled up low-mass star formation in massive star-forming cores in the G333 giant molecular cloud

Cited by in corpus (20)

• The ALMA Survey of 70 $\mu$m Dark High-mass Clumps in Early Stages (ASHES). IX. Physical Properties and Spatial Distribution of Cores in IRDCs
• The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VIII. Dynamics of Embedded Dense Cores
• Establishing the evolutionary timescales of the massive star formation process through chemistry
• The core population and kinematics of a massive clump at early stages: an ALMA view
• Survey of ortho-H${}_2$D${}^{+}$ in high-mass star-forming regions
• A new proxy to estimate the cosmic-ray ionisation rate in dense cores
• Identification of prestellar cores in high-mass star forming clumps via ${\mathrm{H}}_2{\mathrm{D}}^{+}$ observations with ALMA
• The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VI. The core-scale CO-depletion
• The chemical structure of young high-mass star-forming clumps: (II) parsec-scale CO depletion and deuterium fraction of $\mathrm{HC}{\mathrm{O}}^{+}$
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). VII: Chemistry of Embedded Dense Cores
• The 3D structure of CO depletion in high-mass prestellar regions
• Physical and chemical structure of the Serpens filament -- fast formation and gravity-driven accretion
• Parsec-scale cosmic-ray ionisation rate in Orion
• ALMA-IMF XVIII: The assembly of a star cluster: Dense N${}_2$H${}^{+}$ (1-0) kinematics in the massive G351.77 protocluster
• KAgoshima Galactic Object survey with Nobeyama 45-metre telescope by Mapping in Ammonia lines (KAGONMA): Discovery of parsec-scale CO depletion in the Canis Major star-forming region
• Chemical complexity in star formation induced by stellar feedback: cores shock-formed by the supernova remnant W44
• Dense Molecular Ring-like structure in gaseous CO depletion region G34.74-0.12
• CO Depletion in Infrared Dark Clouds
• Synthetic observations using POLARIS: an application to simulations of massive prestellar cores
• Chemical analysis of prestellar cores in Ophiuchus yields short timescales and rapid collapse