Cloud structures in M17 SWex : Possible cloud-cloud collision

Abstract

Using wide-field ${}^{13}$CO ($J=1-0$) data taken with the Nobeyama 45-m telescope, we investigate cloud structures of the infrared dark cloud complex in M17 with SCIMES. In total, we identified 118 clouds that contain 11 large clouds with radii larger than 1 pc. The clouds are mainly distributed in the two representative velocity ranges of 10 $-$ 20 km s${}^{-1}$ and 30 $-$ 40 km s${}^{-1}$. By comparing with the ATLASGAL catalog, we found that the majority of the ${}^{13}$CO clouds with 10 $-$ 20 km s${}^{-1}$ and 30 $-$ 40 km s${}^{-1}$ are likely located at distances of 2 kpc (Sagittarius arm) and 3 kpc (Scutum arm), respectively. Analyzing the spatial configuration of the identified clouds and their velocity structures, we attempt to reveal the origin of the cloud structure in this region. Here we discuss three possibilities: (1) overlapping with different velocities, (2) cloud oscillation, and (3) cloud-cloud collision. From the position-velocity diagrams, we found spatially-extended faint emission between $\sim$ 20 km s${}^{-1}$ and $\sim$ 35 km s${}^{-1}$, which is mainly distributed in the spatially-overlapped areas of the clouds. We also found that in some areas where clouds with different velocities overlapped, the magnetic field orientation changes abruptly. The distribution of the diffuse emission in the position-position-velocity space and the bending magnetic fields appear to favor the cloud-cloud collision scenario compared to other scenarios. In the cloud-cloud collision scenario, we propose that two $\sim$35 km s${}^{-1}$ foreground clouds are colliding with clouds at $\sim$20 km s${}^{-1}$ with a relative velocity of 15 km s${}^{-1}$. These clouds may be substructures of two larger clouds having velocities of $\sim$ 35 km s${}^{-1}$ ($\gtrsim 10^3$ M${}_{\odot }$) and $\sim$ 20 km s${}^{-1}$ ($\gtrsim 10^4$ M${}_{\odot }$), respectively.

34 pages, 13 figures, Accepted for publication in PASJ

References in corpus (42)

• Toward Understanding Massive Star Formation
• The Formation of Massive Stars from Turbulent Cores
• ATLASGAL - The APEX Telescope Large Area Survey of the Galaxy at 870 microns
• Competitive accretion in embedded stellar cluster
• On the Formation of Massive Stars
• Structural Analysis of Molecular Clouds: Dendrograms
• High-Mass Star and Massive Cluster Formation in the Milky Way
• Infrared Dark Clouds: precursors to star clusters
• ATLASGAL --- properties of a complete sample of Galactic clumps
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• Global Star Formation Rates in Disk Galaxies and Circumnuclear Starbursts from Cloud Collisions
• HARP/ACSIS: A submillimetre spectral imaging system on the James Clerk Maxwell Telescope
• Chemistry in Infrared Dark Cloud Clumps: a Molecular Line Survey at 3 mm
• The ALMA Survey of 70 $\mu$m dark High-mass clumps in Early Stages (ASHES). I. Pilot Survey: Clump Fragmentation
• Do cloud-cloud collisions trigger high-mass star formation? I. Small cloud collisions
• Molecular Clouds Toward the Super Star Cluster NGC3603; Possible Evidence for a Cloud-Cloud Collision in Triggering the Cluster Formation
• Trigonometric Parallaxes of Massive Star Forming Regions: VIII. G12.89+0.49, G15.03-0.68 (M17) and G27.36-0.16
• A Massive Prestellar Clump Hosting no High-Mass Cores
• Isolating signatures of major cloud-cloud collisions using position-velocity diagrams
• On-The-Fly Observing System of the Nobeyama 45-m and ASTE 10-m Telescopes
• CHIMPS: the ${}^{13}$CO/C${}^{18}$O (J=3-2) Heterodyne Inner Milky Way Plane Survey
• Unveiling a network of parallel filaments in the Infrared Dark Cloud G14.225-0.506
• Graph-based interpretation of the Molecular Interstellar Medium Segmentation
• Filamentary Accretion Flows in the Infrared Dark Cloud G14.225-0.506 Revealed by ALMA
• Infall Signatures in a Prestellar Core embedded in the High-Mass 70 $\mu$m Dark IRDC G331.372-00.116
• GMC Collisions as Triggers of Star Formation. III. Density and Magnetically Regulated Star Formation
• Dense core properties in the Infrared Dark cloud G14.225-0.506 revealed by ALMA
• Evidence for Delayed Massive Star Formation in the M17 Proto-OB Association
• What is controlling the fragmentation process in the Infrared Dark Cloud G14.225-0.506? Differet level of fragmentation in twin hubs
• Distance to G14.33-0.64 in the Sagittarius Spiral Arm: H2O Maser Trigonometric Parallax with VERA
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) 2: Possible evidence for formation of NGC~6618 cluster in M17 by cloud-cloud collision
• Rapid Circumstellar Disk Evolution and an Accelerating Star Formation Rate in the Infrared Dark Cloud M17 SWex
• Automated reduction of submillimetre single-dish heterodyne data from the James Clerk Maxwell Telescope using ORAC-DR
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) : Molecular clouds toward W33 ; possible evidence for a cloud-cloud collision triggering O star formation
• Cloud-cloud collision in the DR 21 cloud as a trigger of massive star formation
• Nobeyama 45-m mapping observations toward nearby molecular clouds, Orion A, Aquila Rift, and M17: Project overview
• Oscillations in the stable starless core Barnard 68
• Cluster formation in the W40 and Serpens South complex triggered by the expanding HII region
• GMC Collisions as Triggers of Star Formation. VII. The Effect of Magnetic Field Strength on Star Formation
• Near-Infrared Imaging Polarimetry toward M17 SWex
• Large-scale molecular gas distribution in the M17 cloud complex: dense gas conditions of massive star formation?
• Multi-scale analysis of the Monoceros OB 1 star-forming region: I. The dense core population

Cited by in corpus (5)

• Cloud-cloud collisions and triggered star formation
• MHD simulations of dense core collision
• Stars Born in the Wind: M82's Outflow and Halo Star Formation
• Accretion vs. Core-Filament Collision: Implications for Streamer Formation in Per-emb-2
• Bipolar Molecular Outflow from M17