Core orientations and magnetic fields in isolated molecular clouds

Abstract

Molecular clouds are sites of star formation. Magnetic fields are believed to play an important role in their dynamics and shaping morphology. We aim to study any possible correlation that might exist between the magnetic fields orientation inside the clouds and the magnetic fields at envelope scales and their connection with respect to the observed morphology of the selected clouds. We examine the magnetic field orientation towards the clouds L1512, L1523, L1333, L1521E, L1544, L1517, L1780, and L183 using optical and \textit{Planck} polarization observations. We also found the correlation between the ambient magnetic field and core orientations derived using \textit{Astrodendrogram} on the \textit{Herschel} 250 $\mu$m data. We find that the magnetic fields derived from optical and \textit{Planck} agree with each other. The derived magnetic fields are aligned along the observed emission of each cloud as seen in \textit{Herschel} 250 $\mu$m data. We also find that the relative orientation between the cores and the magnetic fields is random. This lack of correlation may arise due to the fact that the core orientation could also be influenced by the different magnetization within individual clouds at higher densities or the feedback effects which may vary from cloud to cloud. The estimated magnetic field strength and the mass-to-flux ratio suggest that all the clouds are in a magnetically critical state except L1333, L1521E, and L183 where the cloud envelope could be strongly supported by the magnetic field lines.

19 pages, 5 figures and 5 tables; Accepted for publication in MNRAS

References in corpus (23)

• Theory of Star Formation
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• Structural Analysis of Molecular Clouds: Dendrograms
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• Tracing Magnetic Fields with Aligned Grains
• A Large Catalog of Accurate Distances to Local Molecular Clouds: The Gaia DR2 Edition
• A Compendium of Distances to Molecular Clouds in the Star Formation Handbook
• Magnetically Aligned Velocity Anisotropy in the Taurus Molecular Cloud
• Deuterated methanol in the pre-stellar core L1544
• Formation of Magnetized Prestellar Cores with Ambipolar Diffusion and Turbulence
• Optical polarimetry toward the Pipe nebula: Revealing the importance of the magnetic field
• 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
• An application of an optimal statistic for characterising relative orientations
• Probing Inward Motions in Starless Cores Using The HCN J = 1-0 Hyperfine Transitions : A Pointing Survey Toward Central Regions
• The Distances to Molecular Clouds at High Galactic Latitudes based on GAIA DR2
• SCUBA polarisation observations of the magnetic fields in the prestellar cores L1498 and L1517B
• Magnetic fields in cometary globules - IV. LBN 437
• The Link between Magnetic-field Orientations and Star Formation Rates
• Comparison of Prestellar Core Elongations and Large-Scale Molecular Cloud Structures in the Lupus I Region
• Probing the magnetic fields in L1415 and L1389
• Interstellar extinction, polarization, and grain alignment in the Sh 2-185 (IC 59 and IC 63) region
• Distance, magnetic field and kinematics of a filamentary cloud LDN 1157