NH3 Observations of the Infrared Dark Cloud G28.34+0.06

Abstract

We present observations of the \nh3 (J,K) = (1,1) and (2,2) inversion transitions toward the infrared dark cloud G28.34+0.06, using the Very Large Array. Strong NH3 emission is found to coincide well with the infrared absorption feature in this cloud. The northern region of G28.34+0.06 is dominated by a compact clump (P2) with a high rotation temperature (29 K), large line width (4.3 km s${}^{-1}$), and is associated with strong water maser (240 Jy) and a 24 $\mu$m point source with far IR luminosity of $10^3$ \lsun. We infer that P2 has embedded massive protostars although it lies in the 8 $\mu$m absorption region. The southern region has filamentary structures. The rotation temperature in the southern region decreases with the increase of the integrated NH3 intensity, which indicates an absence of strong internal heating in these clumps. In addition, the compact core P1 in the south has small line width (1.2 km s${}^{-1}$) surrounded by extended emission with larger line width (1.8 km s${}^{-1}$), which suggests a dissipation of turbulence in the dense part of the cloud. Thus, we suggest that P1 is at a much earlier evolutionary stage than P2, possibly at a stage that begins to form a cluster with massive stars.

arXiv comment13 pages, 3 figures. Accepted to ApJ Letters

References in corpus (11)

• Embedded Clusters in Molecular Clouds
• Infrared Dark Clouds: precursors to star clusters
• Ammonia in Infrared Dark Clouds
• A Catalog of MSX Infrared Dark Cloud Candidates
• Massive Protostars in the Infrared Dark Cloud MSXDC G034.43+00.24
• High Mass Starless Cores
• High mass star formation in the infrared dark cloud G11.11-0.12
• Caught in the act: The Onset of massive star formation
• Radio-millimetre investigation of galactic infrared dark clouds
• The G11.11-0.12 Infrared-Dark Cloud: Anomalous Dust and a Non-Magnetic Isothermal Model
• Interactions between a Bright YSO and the MSX Infrared-Dark Cloud G79.3+0.3: An Early Stage of Triggered Star Formation?

Cited by in corpus (62)

• Hierarchical fragmentation and differential star formation in the Galactic "Snake": infrared dark cloud G11.11-0.12
• A Class I and Class II Methanol Maser Survey of Extended Green Objects (EGOs) from the GLIMPSE Survey
• Fragmentation at the Earliest Phase of Massive Star Formation
• Fragmentation of Molecular Clumps and Formation of Protocluster
• Hierarchical Fragmentation and Jet-like Outflows in IRDC G28.34+0.06, a Growing Massive Protostar Cluster
• Mid-Infrared Extinction Mapping of Infrared Dark Clouds: Probing the Initial Conditions for Massive Stars and Star Clusters
• The Earliest Phases of Star Formation (EPoS): A Herschel Key Program - The precursors to high-mass stars and clusters
• Unveiling a network of parallel filaments in the Infrared Dark Cloud G14.225-0.506
• An Infrared through Radio Study of the Properties and Evolution of IRDC Clumps
• Understanding star formation in molecular clouds II. Signatures of gravitational collapse of IRDCs
• Very Large Array Observations of Ammonia in Infrared-Dark Clouds I: Column Density and Temperature Structure
• GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XV. Steady Accretion from Global Collapse to Core Feeding in Massive Hub-filament System SDC335
• Protostellar Outflow Heating in a Growing Massive Protocluster
• Properties of dense cores in clustered massive star-forming regions at high angular resolution
• IRDC G030.88+00.13: A Tale of Two Massive Clumps
• Kinematic structure of massive star-forming regions - I. Accretion along filaments
• The Core Mass Function in the Massive Protocluster G286.21+0.17 revealed by ALMA
• Formation of Massive Protostellar Clusters -- Observations of Massive 70 $\mu$m Dark Molecular Clouds
• The Onset of Massive Star Formation: The Evolution of Temperature and Density Structure in an Infrared Dark Cloud
• Massive and low-mass protostars in massive "starless" cores
• Very Large Array Observations of Ammonia in Infrared-Dark Clouds II: Internal Kinematics
• The Origin of OB Clusters: From 10 pc to 0.1 pc
• Widespread Molecular Outflows in the Infrared Dark Cloud G28.37+0.07: Indications of Orthogonal Outflow-Filament Alignment
• Cloud structure of three Galactic infrared dark star-forming regions from combining ground and space based bolometric observations
• The Darkest Shadows: Deep Mid-Infrared Extinction Mapping of a Massive Protocluster
• Outflow detection in a 70 $\mu$m dark high-mass core
• Magnetic fields in the early stages of massive star formation as revealed by ALMA
• Deuterium Fractionation as an Evolutionary Probe in the Infrared Dark Cloud G28.34+0.06
• Are Infrared Dark Clouds Really Quiescent?
• The RMS Survey: Ammonia mapping of the environment of massive young stellar objects
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• ALMA observations of NGC 6334S $-$ I: Forming massive stars and cluster in subsonic and transonic filamentary clouds
• Initial Fragmentation in the Infrared Dark Cloud G28.53-0.25
• Physical Conditions of the Earliest Phases of Massive Star Formation: Single-Dish and Interferometric Observations of Ammonia and CCS in Infrared Dark Clouds
• A Galactic survey of radio jets from massive protostars
• VLA Observations of the Infrared Dark Cloud G19.30+0.07
• Dynamical cloud formation traced by atomic and molecular gas
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XII: Fragmentation and multi-scale gas kinematics in protoclusters G12.42+0.50 and G19.88-0.53
• Mother of Dragons: A Massive, quiescent core in the dragon cloud (IRDC G028.37+00.07)
• The ALMA Survey of 70 μm Dark High-mass Clumps in Early Stages (ASHES). VI. The core-scale CO-depletion
• The Comparison of Physical Properties Derived from Gas and Dust in a Massive Star-Forming Region
• The evolution of temperature and density structures of OB cluster-forming molecular clumps
• High Velocity Molecular Outflows In Massive Cluster Forming Region G10.6-0.4
• Multiple low-turbulence starless cores associated with intermediate- to high-mass star formation
• Multi-generation massive star-formation in NGC3576
• The chemical structure of young high-mass star-forming clumps: (I) Deuteration
• Protostar mass functions in young clusters
• From dusty filaments to massive stars: The case of NGC 7538 S
• Mid-J CO shock tracing observations of infrared dark clouds II Low-J CO constraints on excitation, depletion, and kinematics
• Temperature and kinematics of protoclusters with intermediate and high-mass stars: the case of IRAS 05345+3157
• Infrared Dark Clouds in the Small Magellanic Cloud?
• Kinematic and Thermal Structure at the onset of high-mass star formation
• The physical conditions in IRDC clumps from Herschel HIFI observations of H2O
• High Angular Resolution Observations of Four Candidate BLAST High-Mass Starless Cores
• Highly structured turbulence in high-mass star formation: an evolved infrared dark cloud G35.20-0.74 N
• Filament Intersections and Cold Dense Cores in Orion A North
• Star formation in IRDC G31.97+0.07
• The JCMT BISTRO-3 Survey: Variation of magnetic field orientations on parsec and sub-parsec scales in the massive star-forming region G28.34+0.06
• Deviation from a Continuous and Universal Turbulence Cascade in NGC 6334 due to Massive Star Formation Activity
• Millimeter and far-IR study of the IRCD SDC 341.232-0.268
• Unlocking accretion rate diagnostics for high-mass protostars using JWST/MIRI HI lines