The Snake Filament: A study of polarization and kinematics

Abstract

The role of magnetic fields in the formation of dense filamentary structures in molecular clouds is critical for understanding the star formation process. The Snake filament in or close to the Pipe Nebula s neighboring, a prominent example of such structures, offers an ideal environment to study the interplay between magnetic fields and gas dynamics in the early stages of star formation. This study aims to investigate how magnetic fields influence the structure and dynamics of the Snake filament, using both polarization data and molecular line observations. Our goal is to understand the role of magnetic fields in shaping the filamentary structure and explore the kinematics within the filament. We conducted polarization observations in the optical and near-infrared bands using the 1.6 m and 60 cm telescopes at the Observatorio do Pico dos Dias/Laboratorio Nacional de Astrof\isica (OPD/LNA). Molecular line observations of the C18O and 13CO lines were obtained using the IRAM 30m telescope. We analyzed the data to characterize polarization and gas properties within the filament, with a focus on understanding the magnetic field orientation and its relationship with the filament s structure. Our findings reveal that the polarization vectors align with the filament s spine, indicating a magnetic field structure that is predominantly parallel to the filament at lower-density regions. A velocity gradient along the filament is observed in both C18O and 13CO lines, with C18O tracing the denser regions of the gas. The polarization efficiency decreases with increasing visual extinction, consistent with reduced grain alignment in higher-density regions. The filament s mass-to-length ratio is below the critical value required for gravitational collapse, indicating stability.

References in corpus (20)

• The Gaia mission
• Gaia Data Release 3: Summary of the content and survey properties
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Radiative torques: Analytical Model and Basic Properties
• SkyMapper Southern Survey: Second Data Release (DR2)
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia EDR3 stars brighter than G=18.5
• A Classification Scheme for Young Stellar Objects Using the WIDE-FIELD INFRARED SURVEY EXPLORER AllWISE Catalog: Revealing Low-Density Star Formation in the Outer Galaxy
• A parsec-scale Galactic 3D dust map out to 1.25 kpc from the Sun
• Parameters of 220 million stars from Gaia BP/RP spectra
• Three-dimensional extinction maps: Inverting inter-calibrated extinction catalogues
• Internal calibration of Gaia BP/RP low-resolution spectra
• The Earliest Phases of Star formation observed with Herschel (EPoS): The dust temperature and density distributions of B68
• On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
• Magnetized filamentary gas flows feeding the young embedded cluster in Serpens South
• An application of an optimal statistic for characterising relative orientations
• Deep Near-Infrared Survey of the Pipe Nebula II: Data, Methods, and Dust Extinction Maps
• The magnetic properties of the protostellar core IRAS 15398-3359
• On the evolution of the observed Mass-to-Length relationship for star-forming filaments
• The SPHEREx Target List of Ice Sources (SPLICES)
• Unveiling the role of magnetic fields in an accreting filament onto a young protocluster