The Cassiopeia Filament: A Blown Spur of the Local Arm

Abstract

We present wide-field and high-sensitivity CO(1-0) molecular line observations toward the Cassiopeia region, using the 13.7m millimeter telescope of the Purple Mountain Observatory (PMO). The CO observations reveal a large-scale highly filamentary molecular cloud within the Galactic region of 132\fdg0\,$\ge$\,$l$\,$\ge$\,122\fdg0 and -1\fdg0\,$\le$\,$b$\,$\le$\,3\fdg0 and the velocity range from approximately +1 to +4 km/s. The measured length of the large-scale filament, referred to as the Cassiopeia Filament, is about 390 pc. The observed properties of the Cassiopeia Filament, such as length, column density, and velocity gradient, are consistent with those synthetic large-scale filaments in the inter-arm regions. Based on its observed properties and location on the Galactic plane, we suggest that the Cassiopeia Filament is a spur of the Local arm, which is formed due to the galactic shear. The western end of the Cassiopeia Filament shows a giant arc-like molecular gas shell, which is extending in the velocity range from roughly -1 to +7 km/s. Finger-like structures, with systematic velocity gradients, are detected in the shell. The CO kinematics suggest that the large shell is expanding at a velocity of ~6.5 km/s. Both the shell and finger-like structures outline a giant bubble with a radius of ~16 pc, which is likely produced by stellar wind from the progenitor star of a supernova remnant. The observed spectral linewidths suggest that the whole Cassiopeia Filament was quiescent initially until its west part was blown by stellar wind and became supersonically turbulent.

arXiv comment46 pages, 19 figures, to be published by the AJ

References in corpus (80)

• Gaia Data Release 2. Summary of the contents and survey properties
• PARSEC: stellar tracks and isochrones with the PAdova and TRieste Stellar Evolution Code
• Theory of Star Formation
• The Milky Way in Molecular Clouds: A New Complete CO Survey
• The Spitzer c2d Legacy Results: Star Formation Rates and Efficiencies; Evolution and Lifetimes
• A new generation of PARSEC-COLIBRI stellar isochrones including the TP-AGB phase
• The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
• Clouds, filaments and protostars: the Herschel Hi-GAL Milky Way
• Trigonometric Parallaxes Of High-Mass Star Forming Regions: Our View Of The Milky Way
• The persistent cosmic web and its filamentary structure I: Theory and implementation
• Re-examining Larson's Scaling Relationships in Galactic Molecular Clouds
• Physical Conditions in Regions of Star Formation
• High-Mass Star and Massive Cluster Formation in the Milky Way
• Filamentary structure of star-forming complexes
• The Optical to Mid-Infrared Extinction Law Based on the APOGEE, Gaia DR2, Pan-STARRS1, SDSS, APASS, 2MASS and WISE Surveys
• The VLA Low-frequency Sky Survey
• Low Virial Parameters in Molecular Clouds: Implications for High Mass Star Formation and Magnetic Fields
• The Very Large Array Low-frequency Sky Survey Redux (VLSSr)
• The Formation and Destruction of Molecular Clouds and Galactic Star Formation
• Gravity or Turbulence? The velocity dispersion-size relation
• Clouds as Turbulent Density Fluctuations. Implications for pressure confinement and spectral line data interpretation
• The Milky Way Project First Data Release: A Bubblier Galactic Disk
• Star formation near the Sun is driven by expansion of the Local Bubble
• CO-dark gas and molecular filaments in Milky Way type galaxies
• The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg
• The "Nessie" Nebula: Cluster Formation in a Filamentary Infrared Dark Cloud
• Collapse and Fragmentation in Finite Sheets
• Filaments in Simulations of Molecular Cloud Formation
• Massive stars and the energy balance of the ISM. I. The impact of an isolated 60 Msun star
• On the origin of non self-gravitating filaments in the ISM
• Radio emission from Supernova Remnants
• On the Structure of the Orion A Cloud and the Formation of the Orion Nebula Cluster
• Large-scale filaments associated with Milky Way spiral arms
• Giant Molecular Filaments in the Milky Way
• The Bones of the Milky Way
• The dangers of being trigger--happy
• ATLASGAL -- A Galaxy-wide sample of dense filamentary structures
• The modelling of feedback in star formation simulations
• The Cloud Factory I: Generating resolved filamentary molecular clouds from galactic-scale forces
• The Hi-GAL compact source catalogue -- II. The 360° catalogue of clump physical properties
• The Physical Properties of Large-Scale Galactic Filaments
• The Musca cloud: A 6 pc-long velocity-coherent, sonic filament
• The Skeleton of the Milky Way
• The Galactic Distribution of Large HI Shells
• OB associations and their origins
• A Sino-German lambda6 cm polarization survey of the Galactic plane I. Survey strategy and results for the first survey region
• Interstellar matter and star formation in W5-E - A Herschel view
• Axisymmetric circumstellar interaction in supernovae
• A Sino-German 6cm polarization survey of the Galactic plane VII. Small supernova remnants
• The fully developed remnant of a neutrino-driven supernova: Evolution of ejecta structure and asymmetries in SNR Cassiopeia A
• A Census of Large-Scale ($\ge$ 10 pc), Velocity-Coherent, Dense Filaments in the Northern Galactic Plane: Automated Identification Using Minimum Spanning Tree
• Probing accretion of ambient cloud material into the Taurus B211/B213 filament
• From diffuse gas to dense molecular cloud cores
• What can simulated molecular clouds tell us about real molecular clouds?
• Giant molecular filaments in the Milky Way II: The fourth Galactic quadrant
• Bullets in a Core Collapse Supernova Remnant: The Vela Remnant
• Star-forming content of the giant molecular filaments in the Milky Way
• A 500 pc filamentary gas wisp in the disk of the Milky Way
• Local spiral structure based on the Gaia EDR3 parallaxes
• Linear relation for wind-blown bubble sizes of main-sequence OB stars in a molecular environment and implication for supernova progenitors
• Young Stellar Objects and Triggered Star Formation in the Vulpecula OB Association
• Triggered Star Formation and Dust around Mid-Infrared-Identified Bubbles
• Massive molecular outflows associated with UCHII/HII regions
• The evolution of Giant Molecular Filaments
• SEDIGISM: The kinematics of ATLASGAL filaments
• A new catalog of HI supershell candidates in the outer part of the Galaxy
• A Morphological Classification of 18190 Molecular Clouds Identified in ${}^{12}$CO Data from the MWISP Survey
• Hydrodynamic modelling of ejecta shrapnel in the Vela supernova remnant
• The Molecular Structures of Local Arm and Perseus Arm in the Galactic Region of l=[139.75,149.75]${}^{\circ }$, b=[-5.25,5.25]${}^{\circ }$
• N131: A dust bubble born from the disruption of a gas filament
• Hydrodynamic simulations of mechanical stellar feedback in a molecular cloud formed by thermal instability
• Magnetic field structure of IC 63 and IC 59 associated to H II region - Sh 185
• Distances to molecular clouds in the second Galactic quadrant
• Synthetic Large-Scale Galactic Filaments -- on their Formation, Physical Properties, and Resemblance to Observations
• OGHReS: Large-scale filaments in the outer Galaxy
• 3D modeling from the onset of the SN to the full-fledged SNR: Role of an initial ejecta anisotropy on matter mixing
• A wide-field CO survey towards the California Molecular Filament
• Discovery of a pre-existing molecular filament associated with supernova remnant G127.1+0.5
• The infrared and molecular environment surrounding the Wolf-Rayet star WR130
• Examinations of CO completeness based on three independent CO surveys

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• Large-scale Velocity-coherent Filaments in the SEDIGISM Survey: Association with Spiral Arms and Fraction of Dense Gas
• Investigations of MWISP Filaments. I. Filament Identification and Analysis Algorithms, and Source Catalogue
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