The Magnetic Field of Cloud 3 in L204

Abstract

The L204 dark cloud complex is a nearby filamentary structure in Ophiuchus North that has no signs of active star formation. Past studies show that L204 is interacting with the nearby runaway O star, $\zeta$ Oph, and hosts a magnetic field that is coherent across parsec-length scales. Near-infrared $H$-band (1.6$\mu$m) linear polarization measurements were obtained for 3,896 background stars across a $1°\times 1.5°$ region centered on the dense Cloud 3 in L204, using the Mimir near-infrared instrument on the 1.8m Perkins Telescope. Analysis of these observations reveals both large-scale properties and small-scale changes in the magnetic field direction in Cloud 3. In the northern and western $\zeta$ Oph facing regions of the cloud, the magnetic field appears to be pushed up against the face of the cloud. This may indicate that the UV flux from $\zeta$ Oph has compressed the magnetic field on the western edge of L204. The plane-of-sky magnetic field strength is estimated to be $\sim 11-26$ $\mu$G using the Chandrasekhar-Fermi method. The polarimetry data also reveal that the polarization efficiency (PE $\equiv P_{\mathrm{H}}/A_{\mathrm{V}}$) steadily decreases with distance from $\zeta$ Oph ($-0.09\pm 0.03\%{\mathrm{mag}}^{-1}{\mathrm{pc}}^{-1}$). Additionally, power-law fits of PE versus $A_{\mathrm{V}}$ for localized samples of probe stars show steeper negative indices with distance from $\zeta$ Oph. Both findings highlight the importance of external illumination, here from $\zeta$ Oph, in aligning dust grains to embedded magnetic fields.

arXiv comment13 pages, 14 figures, 1 table

References in corpus (17)

• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Validation of the new Hipparcos reduction
• Control of star formation by supersonic turbulence
• Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models
• Radiative torques: Analytical Model and Basic Properties
• Mapping the interstellar dust with near-infrared observations: An optimized multi-band technique
• Stellar Populations in the Large Magellanic Cloud from 2MASS
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• 2MASS wide field extinction maps: II. The Ophiuchus and the Lupus cloud complexe
• A Full-sky, High-resolution Atlas of Galactic 12 micron Dust Emission with WISE
• Observational Constraints on Interstellar Grain Alignment
• GRAIN ALIGNMENT IN THE TAURUS DARK CLOUD
• The Spitzer Survey of Interstellar Clouds in the Gould Belt. V. Ophiuchus North Observed with IRAC and MIPS
• Resolved Magnetic Field Mapping of a Molecular Cloud Using GPIPS
• Correlation between Interstellar Polarization and Dust Temperature: Alignment of Grains by Radiative Torques is Ubiquitous?
• Molecular Clouds Around a Run-away O Star, zeta Oph
• Toward Understanding the Origin of Turbulence in Molecular Clouds: Small Scale Structures as Units of Dynamical Multi-Phase Interstellar Medium

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