The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud

Abstract

We present new NH3 (1,1), (2,2), and (4,4) observations from the Karl G. Jansky Very Large Array (VLA) compiled with work in the literature to explore the range of conditions observed in young, massive star-forming regions. To sample the effects of evolution independent from those of distance/resolution, abundance, and large-scale environment, we compare clumps in different evolutionary stages within a single Infrared Dark Cloud (IRDC), G32.02+0.06. We find that the early stages of clustered star formation are characterized by dense, parsec-scale filamentary structures interspersed with complexes of dense cores (<0.1 pc cores clustered in complexes separated by ~1 pc) with masses from about 10 to 100 Msun. The most quiescent core is the most extended while the star-forming cores are denser and more compact, showing very similar column density structure before and shortly after the onset of massive star formation, with peak surface densities >~ 1 g cm^-2. Quiescent cores and filaments show smoothly varying temperatures from 10-20 K, rising to over 40 K in star-forming cores. We calculate the virial parameters for 16 cores and find that the level of support provided by turbulence is generally insufficient to support them against gravitational collapse (alpha_vir ~ 0.6). The star-forming filaments show smooth velocity fields, punctuated by discontinuities at the sites of active star formation. We discuss the Massive Molecular Filament (MMF; M > 10^5 Msun, l > 60 pc) hosting the IRDC, hypothesizing that it may have been shaped by previous generations of massive stars.

arXiv commentAccepted in ApJ

References in corpus (72)

• Embedded Clusters in Molecular Clouds
• The Photodetector Array Camera and Spectrometer (PACS) on the Herschel Space Observatory
• The Herschel-SPIRE instrument and its in-flight performance
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• Cold Dark Clouds: The Initial Conditions for Star Formation
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• The Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• High-Mass Proto-Stellar Candidates - II : Density structure from dust continuum and CS emission
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• Infrared Dark Clouds: precursors to star clusters
• Physical Properties and Galactic Distribution of Molecular Clouds identified in the Galactic Ring Survey
• The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• Low Virial Parameters in Molecular Clouds: Implications for High Mass Star Formation and Magnetic Fields
• The Bolocam Galactic Plane Survey: Survey Description and Data Reduction
• Ammonia in Infrared Dark Clouds
• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• How Many Infrared Dark Clouds can form Massive Stars and Clusters?
• The Bolocam Galactic Plane Survey -- II. Catalog of the Image Data
• The Origin of Massive O-type Field Stars. Part II: Field O stars as runaways
• The Green Bank Telescope HII Region Discovery Survey II. The Source Catalog
• Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• Fragmentation at the Earliest Phase of Massive Star Formation
• A general catalogue of 6.7 GHz methanol masers. I: data
• Fragmentation and mass segregation in the massive dense cores of Cygnus X
• The Co-ordinated Radio and Infrared Survey for High Mass Star Formation (The CORNISH Survey) - I. Survey Design
• The Co-ordinated Radio and Infrared Survey for High-Mass Star Formation - II. Source Catalogue
• Characterizing Precursors to Stellar Clusters with Herschel
• Probing the initial conditions of high-mass star formation. II. Fragmentation, stability, and chemistry
• The Bolocam Galactic Plane Survey IX: Data Release 2 and Outer Galaxy Extension
• New Catalogs of Compact Radio Sources in the Galactic Plane
• The data reduction pipeline for the Hi-GAL survey
• The Bolocam Galactic Plane Survey. VII. Characterizing the Properties of Massive Star-Forming Regions
• From the Convergence of Filaments to Disk-Outflow Accretion: Massive-Star Formation in W33A
• Quantifying Observational Projection Effects Using Molecular Cloud Simulations
• Early stages of cluster formation: fragmentation of massive dense cores down to ~1000 AU
• An Infrared through Radio Study of the Properties and Evolution of IRDC Clumps
• Molecular clouds and clumps in the Boston University-Five College Radio Astronomy Observatory Galactic Ring Survey
• Multi-wavelength observations of Southern Hot Molecular Cores traced by methanol masers - I. Ammonia and 24 GHz Continuum Data
• NH3 Observations of the Infrared Dark Cloud G28.34+0.06
• Search for starless clumps in the ATLASGAL survey
• Very Large Array Observations of Ammonia in Infrared-Dark Clouds I: Column Density and Temperature Structure
• Excitation and Disruption of a Giant Molecular Cloud by the Supernova Remnant 3C391
• Massive Quiescent Cores in Orion: Dynamical State Revealed by High-Resolution Ammonia Maps
• The Green Bank Telescope HII Region Discovery Survey: III. Kinematic Distances
• Is protostellar heating sufficient to halt fragmentation? A case study of the massive protocluster G8.68-0.37
• SMA observations of Infrared Dark Clouds: A tale of two cores
• Fragmentation and OB Star Formation in High-Mass Molecular Hub-Filament System
• Properties of dense cores in clustered massive star-forming regions at high angular resolution
• The Bolocam Galactic Plane Survey. VIII. A Mid-Infrared Kinematic Distance Discrimination Method
• IRDC G030.88+00.13: A Tale of Two Massive Clumps
• Digging into NGC 6334I(N): Multiwavelength Imaging of a Massive Protostellar Cluster
• Hot ammonia in NGC6334I & I(N)
• Physical and chemical conditions in methanol maser selected hot-cores and UCHII regions
• Molecular and Ionic shocks in the Supernova Remnant 3C391
• Detection of Far-Infrared Water Vapor, Hydroxyl, and Carbon Monoxide Emissions from the Supernova Remnant 3C 391
• First Results from a 1.3 cm EVLA Survey of Massive Protostellar Objects: G35.03+0.35
• Hot high-mass accretion disk candidates
• VLA Observations of the Infrared Dark Cloud G19.30+0.07
• The clustered nature of star formation. Pre--main-sequence clusters in the star-forming region NGC 602/N90 in the Small Magellanic Cloud
• A bright radio HH object with large proper motions in the massive star-forming region W75N
• The Comparison of Physical Properties Derived from Gas and Dust in a Massive Star-Forming Region
• New Wolf-Rayet star and its circumstellar nebula in Aquila
• Spatially Resolved Low Frequency VLA observations of the Supernova Remnant 3C 391
• Reliability of NH3 as the temperature probe of cold cloud cores
• Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157
• The initial conditions of high-mass star formation: radiative transfer models of IRDCs seen in the Herschel Hi-GAL survey
• An 80 pc Long Massive Molecular Filament in the Galactic Mid-Plane
• Subspace Least Square Approach for Drift Removal with Application to Herschel Data

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