Kinematics and star formation of hub-filament systems in W49A

Abstract

W49A is a prominent giant molecular cloud (GMC) that exhibits strong star formation activities, yet its structural and kinematic properties remain uncertain. Our study aims to investigate the large-scale structure and kinematics of W49A, and elucidate the role of filaments and hub-filament systems (HFSs) in its star formation activity. We utilized continuum data from Herschel and the James Clerk Maxwell Telescope (JCMT) as well as the molecular lines 12CO (3-2), 13CO (3-2), and C18O (3-2) to identify filaments and HFS structures within W49A. Further analysis focused on the physical properties, kinematics, and mass transport within these structures. Additionally, recombination line emission from the H I/OH/Recombination (THOR) line survey was employed to trace the central H II region and ionized gas. Our findings reveal that W49A comprises one blue-shifted (B-S) HFS and one red-shifted (R-S) HFS, each with multiple filaments and dense hubs. Notably, significant velocity gradients were detected along these filaments, indicative of material transport toward the hubs. High mass accretion rates along the filaments facilitate the formation of massive stars in the HFSs. Furthermore, the presence of V-shaped structures around clumps in position-velocity diagrams suggests ongoing gravitational collapse and local star formation within the filaments. Our results indicate that W49A consists of one R-S HFS and one B-S HFS, and that the material transport from filaments to the hub promotes the formation of massive stars in the hub. These findings underscore the significance of HFSs in shaping the star formation history of W49A.

arXiv comment19 pages, 22 figures. Accepted to A&A

References in corpus (56)

• Herschel Space Observatory - An ESA facility for far-infrared and submillimetre astronomy
• The Herschel-SPIRE instrument and its in-flight performance
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Hi-GAL: the Herschel infrared Galactic Plane Survey
• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• Filamentary structure of star-forming complexes
• Common-Resolution Convolution Kernels for Space- and Ground-Based Telescopes
• The hierarchical formation of a stellar cluster
• Global collapse of molecular clouds as a formation mechanism for the most massive stars
• Global Hierarchical Collapse In Molecular Clouds. Towards a Comprehensive Scenario
• ATLASGAL --- properties of a complete sample of Galactic clumps
• Filamentary Accretion Flows in the Embedded Serpens South Protocluster
• How Many Infrared Dark Clouds can form Massive Stars and Clusters?
• SDC13 infrared dark clouds: Longitudinally collapsing filaments?
• The Simultaneous Formation of Massive Stars and Stellar Clusters
• Filaments in Simulations of Molecular Cloud Formation
• Unifying low and high mass star formation through density amplified hubs of filaments
• Parallaxes for W49N and G048.60+0.02: Distant Star Forming Regions in the Perseus Spiral Arm
• Large-scale filaments associated with Milky Way spiral arms
• Cloud-cloud collisions and triggered star formation
• Dynamics of cluster-forming hub-filament systems: The case of the high-mass star-forming complex Monoceros R2
• CHIMPS: the ${}^{13}$CO/C${}^{18}$O (J=3-2) Heterodyne Inner Milky Way Plane Survey
• Gravitational collapse of the OMC-1 region
• Filamentary fragmentation in a turbulent medium
• ATLASGAL -- A Galaxy-wide sample of dense filamentary structures
• ATLASGAL --- Complete compact source catalogue: 280\degr\ $<\ell <$ 60\degr
• SPICY: The Spitzer/IRAC Candidate YSO Catalog for the Inner Galactic Midplane
• Aspect Ratio Dependence of the Free-Fall Time for Non-Spherical Symmetries
• High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XI. From inflow to infall in hub-filament systems
• The Hi-GAL catalogue of dusty filamentary structures in the Galactic Plane
• MUSCLE W49 : A Multi-Scale Continuum and Line Exploration of the Most Luminous Star Formation Region in the Milky Way. I. Data and The Mass Structure of the Giant Molecular Cloud
• 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
• The HI/OH/Recombination line survey of the inner Milky Way (THOR): data release 2 and HI overview
• CHIMPS: Physical properties of molecular clumps across the inner Galaxy
• Evidence of high-mass star formation through multi-scale mass accretion in hub-filament-system clouds
• Cloud Structure of Galactic OB Cluster Forming Regions from Combining Ground and Space Based Bolometric Observations
• Formation of the Hub-Filament System G33.92+0.11: Local Interplay between Gravity, Velocity, and Magnetic Field
• Massive Star Formation in the W49 Giant Molecular Cloud: Implications for the Formation of Massive Star Clusters
• Direct observational evidence of the multi-scale, dynamical mass accretion toward a high-mass star forming hub-filament system
• New insights in the HII region G18.88-0.49: hub-filament system and accreting filaments
• Structure and Fragmentation of a high line-mass filament: Nessie
• W49A: A starburst triggered by expanding shells
• Kinematics and Structure of Star-forming Regions: Insights from Cold Collapse Models
• Young Stellar Objects in the Massive Star Forming Region W49
• DR 21 South Filament: a Parsec-sized Dense Gas Accretion Flow onto the DR 21 Massive Young Cluster
• The Massive Stellar Population of W49: A Spectroscopic Survey
• Gravitational collapse and accretion flows in the hub filament system G323.46-0.08
• Mapping the 13CO/C18O abundance ratio in the massive star forming region G29.96-0.02
• High resolution LAsMA ${}^{12}$CO and ${}^{13}$CO observation of the G305 giant molecular cloud complex : II. Effect of feedback on clump properties
• Spiral Structure and Massive Star formation in the Hub-Filament-System G326.27-0.49
• Surveying the Giant HII Regions of the Milky Way with SOFIA: III. W49A
• Star burst in W49N presumably induced by cloud-cloud collision

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• Emergence of high-mass stars in complex fiber networks (EMERGE) V. From filaments to spheroids: the origin of the hub-filament systems
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• FIRESTORM I: Stellar Feedback and Gas Kinematics in the Evolved W40 Hub-Filament System
• Sutra : An integrated framework for identification and characterization of filaments in the interstellar medium
• From inter-filamentary gas to filaments and hubs: gas flows in the Mon R2 hub-filament system