G345.45+1.50: An expanding ring-like structure with massive star formation

Abstract

Ring-like structures in the ISM are commonly associated with high-mass stars. Kinematic studies of large structures in GMCs toward these ring-like structures may help us to understand how massive stars form. The origin and properties of the ring-like structure G345.45+1.50 is investigated through observations of the 13CO(3-2) line. The aim of the observations is to determine the kinematics in the region and to compare physical characteristics estimated from gas emission with those previously determined using dust continuum emission. The 13CO(3-2) line was mapped toward the whole ring using the APEX telescope. The ring is found to be expanding with a velocity of 1.0 km/s, containing a total mass of 6.9e3 Msun, which agrees well with that determined using 1.2 mm dust continuum emission. An expansion timescale of 3e6 yr and a total energy of 7e46 erg are estimated. The origin of the ring might have been a supernova explosion, since a 35.5 cm source, J165920-400424, is located at the center of the ring without an infrared counterpart. The ring is fragmented, and 104 clumps were identified with diameters of between 0.3 and 1.6 pc, masses of between 2.3 and 7.5e2 Msun, and densities of between 1.0e2 and 1.0e4 cm^-3. At least 18% of the clumps are forming stars, as is shown in infrared images. Assuming that the clumps can be modeled as Bonnor-Ebert spheres, 13 clumps are collapsing, and the rest of them are in hydrostatic equilibrium with an external pressure with a median value of 4e4 K cm^-3. In the region, the molecular outflow IRAS 16562-3959 is identified, with a velocity range of 38.4 km/s, total mass of 13 Msun, and kinematic energy of 7e45 erg. Finally, five filamentary structures were found at the edge of the ring with an average size of 3 pc, a width of 0.6 pc, a mass of 2e2 Msun, and a column density of 6e21 cm^-2.

References in corpus (30)

• The Initial Mass Function of Stars: Evidence for Uniformity in Variable Systems
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• Characterizing interstellar filaments with Herschel in IC5146
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• Large-Scale Structure of the Molecular Gas in Taurus Revealed by High Linear Dynamic Range Spectral Line Mapping
• The mass function of dense molecular cores and the origin of the IMF
• The Second Survey of the Molecular Clouds in the Large Magellanic Cloud by NANTEN. II. Star Formation
• ISO spectroscopy of gas and dust: from molecular clouds to protoplanetary disks
• The Formation of Stellar Clusters: Mass Spectra from Turbulent Molecular Cloud Fragmentation
• The Molonglo Galactic Plane Survey (MGPS-2): Compact Source Catalogue
• The spine of the swan: A Herschel study of the DR21 ridge and filaments in Cygnus X
• A SCUBA survey of Orion, the low-mass end of the core mass function
• Near Infrared Imaging Survey of Bok Globules: Density Structure
• Molecular Rings and the Thickness of Star-Forming Clouds
• Two Mass Distributions in the L 1641 Molecular Clouds: The Herschel connection of Dense Cores and Filaments in Orion A
• GMC Evolutions in the Nearby Spiral Galaxy M33
• Spitzer observations of the Massive star forming complex S254-S258: structure and evolution
• The relationship between the prestellar core mass function and the stellar initial mass function
• Herschel's view of the large-scale structure in the Chamaeleon dark clouds
• The Giant Molecular Cloud associated with RCW 106 -- A 1.2 mm continuum mapping study
• Molecular line mapping of the giant molecular cloud associated with RCW 106 - II. Column density and dynamical state of the clumps
• Mopra CO Observations of the Bubble HII Region RCW120
• A String of Radio Emission Associated with IRAS 16562-3959: A Collimated Jet Emanating from a Luminous Massive YSO
• High Mass Star Formation. III. The Functional Form of the Submillimeter Clump Mass Function
• Massive Clumps in the NGC 6334 Star Forming Region
• A Submillimeter View of Star Formation Near the HII Region KR 140
• Structure and radial equilibrium of filamentary molecular clouds
• Massive star formation in the GMC G345.5+1.0: Spatial distribution of the dust emission
• Exploring GLIMPSE Bubble N107: Multiwavelength Observations and Simulations

Cited by in corpus (6)

• Chemistry of the High-Mass Protostellar Molecular Clump IRAS 16562-3959
• The SOFIA Massive (SOMA) Star Formation Survey. II. High Luminosity Protostars
• The low-mass pre-main-sequence population of Sco OB1
• A wind-blown bubble in the Central Molecular Zone cloud G0.253+0.016
• ALMA Observations of the massive molecular outflow G331.512-0.103 II: physical properties, kinematics, and geometry modeling
• Multiwavelength study of the G345.5+1.5 region