DR 21 South Filament: a Parsec-sized Dense Gas Accretion Flow onto the DR 21 Massive Young Cluster

Abstract

DR21 south filament (DR21SF) is a unique component of the giant network of filamentary molecular clouds in the north region of Cygnus X complex. Unlike the highly fragmented and star-forming active environment it resides, DR21SF exhibits a coherent profile in the column density map with very few star formation signposts, even though the previously reported linear density of the filament is an order of magnitude higher than the thermal stable threshold. We derive the size (3.6~pc by 0.13~pc), temperature (10 to 15~K), and mass (1048~\textit{M${}_{\odot }$}) of DR21SF from Shanghai 65 m TianMa Radio Telescope (TMRT) observations of NH${}_3$ (1, 1) and (2, 2) inversion lines in conjunction with the column density map from our previous work. Star-forming sites are identified along the filament where gas temperature excesses. We find clear gradients in radial velocity and intrinsic line-width along the spine of the filament. The gradients can be well interpreted with a scenario of an accretion flow feeding DR 21 at a mass transfer rate of $1.1\times 10^{-3}$~\textit{M${}_{\odot }$} yr${}^{-1}$. Based on the analysis of its kinematic temperature, intrinsic line-width and mass distribution, we conclude that DR21SF is in an overall trans-critical status, which indicates an early evolutionary stage.

15 pages, 4 figures, to be published in Astrophysical Journal

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Cited by in corpus (14)

• The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
• The DR21(OH) Trident -- Resolving the Massive Ridge into Three Entangled Fibers As the Initial Condition of Cluster Formation
• A global view on star formation: The GLOSTAR Galactic plane survey VIII. Formaldehyde absorption in Cygnus~X
• Gravitational collapse and accretion flows in the hub filament system G323.46-0.08
• Convergent Filaments Contracting Towards an Intermediate-mass Prestellar Core
• Kinematics and star formation of hub-filament systems in W49A
• HI Self-absorption toward the Cygnus X North: From Atomic Filament to Molecular Filament
• Emergence of high-mass stars in complex fiber networks (EMERGE) V. From filaments to spheroids: the origin of the hub-filament systems
• Cloud-cloud collision and star formation in G013.313+0.193
• Different molecular filament widths as tracers of accretion onto filaments
• A High-Mass Young Star-forming Core Escaping from Its Parental Filament
• The TMRT K Band Observations towards 26 Infrared Dark Clouds: NH${}_3$, CCS, and HC${}_3$N
• From inter-filamentary gas to filaments and hubs: gas flows in the Mon R2 hub-filament system
• Unveiling Fiber Networks and Core Formation in the DR21 South Filament