The Submillimeter Polarization Spectrum of M17

Abstract

We present 450 μm polarimetric observations of the M17 molecular cloud obtained with the SHARP polarimeter at the Caltech Submillimeter Observatory. Across the observed region, the magnetic field orientation is consistent with previous submillimeter and far-infrared polarization measurements. Our observations are centered on a region of the molecular cloud that has been compressed by stellar winds from a cluster of OB stars. We have compared these new data with previous 350 μm polarimetry and find an anti-correlation between the 450 to 350 μm polarization magnitude ratio and the ratio of 21 cm to 450 μm intensity. The polarization ratio is lower near the east end of the studied region where the cloud is exposed to stellar winds and radiation. At the west end of the region, the polarization ratio is higher. We interpret the varying polarization spectrum as evidence supporting the radiative alignment torque (RAT) model for grain alignment, implying higher alignment efficiency in the region that is exposed to a higher anisotropic radiation field.

24 pages, 10 figures

References in corpus (6)

• Tracing Magnetic Fields with Aligned Grains
• Placing Confidence Limits on Polarization Measurements
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• Results of SPARO 2003: Mapping Magnetic Fields in Giant Molecular Clouds
• Submillimeter Polarization of Galactic Clouds: A Comparison of 350 micron and 850 micron Data
• Polarized Emission from Interstellar Dust

Cited by in corpus (13)

• Resolving the polarized dust emission of the disk around the massive star powering the HH~80-81 radio jet
• The far-infrared polarization spectrum of Rho Ophiuchi A from HAWC+/SOFIA observations
• Submillimeter Polarization Spectrum in the Vela C Molecular Cloud
• First Observation of the Submillimeter Polarization Spectrum in a Translucent Molecular Cloud
• Studying magnetic fields and dust in M17 using polarized thermal dust emission observed by SOFIA/HAWC+
• The JCMT BISTRO Survey: An 850/450$\mu$m Polarization Study of NGC 2071IR in OrionB
• Submillimeter Polarization Spectrum of the Carina Nebula
• Testing Magnetic Field Models for the Class 0 Protostar L1527
• Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region
• SOFIA Polarization Spectrum of Three Star-Forming Clouds
• Modeling the Far-Infrared Polarization Spectrum of a High-Mass Star Forming Cloud
• The role of radiative torques in the molecular cloud core L43
• Probing Polarization and the Role of Magnetic Fields in Cloud Destruction in the Keyhole Nebula