Formation of Massive Protostellar Clusters -- Observations of Massive 70 $\mu$m Dark Molecular Clouds

Abstract

We present Submillimeter Array (SMA) observations of seven massive molecular clumps which are dark in the far-infrared for wavelengths up to 70 $\mu$m. Our 1.3 mm continuum images reveal 44 dense cores, with gas masses ranging from 1.4 to 77.1 M${}_{\odot }$. Twenty-nine dense cores have masses greater than 8 M${}_{\odot }$ and the other fifteen dense cores have masses between 1.4 and 7.5 M${}_{\odot }$. Assuming the core density follows a power-law in radius $\rho \propto r^{-b}$, the index $b$ is found to be between 0.6 and 2.1 with a mean value of 1.3. The virial analysis reveals that the dense cores are not in virial equilibrium. CO outflow emission was detected toward 6 out of 7 molecular clumps and associated with 17 dense cores. For five of these cores, CO emissions appear to have line-wings at velocities of greater than 30 km s${}^{-1}$ with respect to the source systemic velocity, which indicates that most of the clumps harbor protostars and thus are not quiescent in star formation. The estimated outflow timescale increase with core mass, which likely indicates that massive cores have longer accretion timescale than that of the less massive ones. The fragmentation analysis shows that the mass of low-mass and massive cores are roughly consistent with thermal and turbulent Jeans masses, respectively.

arXiv comment24 pages, 7 figures. Accepted for publication in ApJ

References in corpus (67)

• Astropy: A Community Python Package for Astronomy
• Toward Understanding Massive Star Formation
• Trigonometric Parallaxes of Massive Star Forming Regions: VI. Galactic Structure, Fundamental Parameters and Non-Circular Motions
• The Formation of Massive Stars from Turbulent Cores
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• The Submillimeter Array
• Competitive accretion in embedded stellar cluster
• Structural Analysis of Molecular Clouds: Dendrograms
• High-Mass Star and Massive Cluster Formation in the Milky Way
• Infrared Dark Clouds: precursors to star clusters
• Massive molecular outflows
• Unveiling the Circumstellar Envelope and Disk: A Sub-Arcsecond Survey of Circumstellar Structures
• How to Calculate Molecular Column Density
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• Star formation through gravitational collapse and competitive accretion
• Massive star formation in 100,000 years from turbulent and pressurized molecular clouds
• The Physical Conditions for Massive Star Formation: Dust Continuum Maps and Modeling
• Structure and Evolution of the Envelopes of Deeply Embedded Massive Young Stars
• Low Virial Parameters in Molecular Clouds: Implications for High Mass Star Formation and Magnetic Fields
• Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores
• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• Determination of the gas-to-dust ratio in nearby dense clouds using X-ray absorption measurements
• ATLASGAL --- towards a complete sample of massive star forming clumps
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• Ammonia from cold high-mass clumps discovered in the inner Galactic disk by the ATLASGAL survey
• The Formation of Massive Stars by Accretion Through Trapped Hypercompact HII Regions
• Chemistry in Infrared Dark Cloud Clumps: a Molecular Line Survey at 3 mm
• Fragmentation at the Earliest Phase of Massive Star Formation
• The ALMA Survey of 70 $\mu$m dark High-mass clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation
• Properties of Hi-GAL clumps in the inner Galaxy]{The Hi-GAL compact source catalogue. I. The physical properties of the clumps in the inner Galaxy ($-71.0^{\circ }<\ell <67.0^{\circ }$)
• Fragmentation of Molecular Clumps and Formation of Protocluster
• Mid-Infrared Extinction Mapping of Infrared Dark Clouds II. The Structure of Massive Starless Cores and Clumps
• A Herschel and APEX Census of the Reddest Sources in Orion: Searching for the Youngest Protostars
• Tracing the Mass during Low-Mass Star Formation. III. Models of the Submillimeter Dust Continuum Emission from Class 0 Protostars
• Probing the initial conditions of high-mass star formation. II. Fragmentation, stability, and chemistry
• Hierarchical Fragmentation and Jet-like Outflows in IRDC G28.34+0.06, a Growing Massive Protostar Cluster
• The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
• Collapse-Driven Outflow in Star-Forming Molecular Cores
• A Massive Prestellar Clump Hosting no High-Mass Cores
• Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties
• The seeds of star formation in the filamentary infrared-dark cloud G011.11-0.12
• The Earliest Phases of Star Formation (EPoS): A Herschel Key Program - The precursors to high-mass stars and clusters
• Gravity or turbulence? -III. Evidence of pure thermal Jeans fragmentation at ~0.1 pc scale
• Interferometric observations of magnetic fields in forming stars
• Early stages of cluster formation: fragmentation of massive dense cores down to ~1000 AU
• Fragmentation of massive dense cores down to ~1000 AU: Relation between fragmentation and density structure
• Dense Cores in Perseus: The Influence of Stellar Content and Cluster Environment
• Distinct Chemical Regions in the "Prestellar" Infrared Dark Cloud (IRDC) G028.23-00.19
• NH3 Observations of the Infrared Dark Cloud G28.34+0.06
• Opacity broadening and interpretation of suprathermal CO linewidths: Macroscopic Turbulence and Tangled Molecular Clouds
• The Green Bank Ammonia Survey: Dense Cores Under Pressure in Orion A
• Submillimeter Array Observations of the Molecular Outflow in High-mass Star-forming Region G240.31+0.07
• Protostellar Outflow Heating in a Growing Massive Protocluster
• Unveiling the Early-Stage Anatomy of a Protocluster Hub with ALMA
• Molecular outflows within the filamentary infrared dark cloud G34.43+0.24
• Hierarchical fragmentation in the Perseus molecular cloud: From the cloud scale to protostellar objects
• Simultaneous low- and high-mass star formation in a massive protocluster: ALMA observations of G11.92-0.61
• IRDC G030.88+00.13: A Tale of Two Massive Clumps
• Massive and low-mass protostars in massive "starless" cores
• Gravity or turbulence? IV. Collapsing cores in out-of-virial disguise
• Thermal Jeans fragmentation within 1000 AU in OMC-1S
• Mass Assembly of Stellar Systems and their Evolution with the SMA - 1.3 mm Subcompact Data Release
• The RMS Survey: Ammonia mapping of the environment of massive young stellar objects
• Characterizing the Youngest Herschel-detected Protostars I. Envelope Structure Revealed by CARMA Dust Continuum Observations
• Initial Fragmentation in the Infrared Dark Cloud G28.53-0.25
• A possible observational bias in the estimation of the virial parameter in virialized clumps

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