The JCMT BISTRO Survey: Multi-wavelength polarimetry of bright regions in NGC 2071 in the far-infrared/submillimetre range, with POL-2 and HAWC+

Abstract

Polarized dust emission is a key tracer in the study of interstellar medium and of star formation. The observed polarization, however, is a product of magnetic field structure, dust grain properties and grain alignment efficiency, as well as their variations in the line of sight, making it difficult to interpret polarization unambiguously. The comparison of polarimetry at multiple wavelengths is a possible way of mitigating this problem. We use data from HAWC+/SOFIA and from SCUBA-2/POL-2 (from the BISTRO survey) to analyse the NGC 2071 molecular cloud at 154, 214 and 850 $\mu$m. The polarization angle changes significantly with wavelength over part of NGC 2071, suggesting a change in magnetic field morphology on the line of sight as each wavelength best traces different dust populations. Other possible explanations are the existence of more than one polarization mechanism in the cloud or scattering from very large grains. The observed change of polarization fraction with wavelength, and the 214-to-154 $\mu$m polarization ratio in particular, are difficult to reproduce with current dust models under the assumption of uniform alignment efficiency. We also show that the standard procedure of using monochromatic intensity as a proxy for column density may produce spurious results at HAWC+ wavelengths. Using both long-wavelength (POL-2, 850 $\mu$m) and short-wavelength (HAWC+, $\lesssim 200\mu$m) polarimetry is key in obtaining these results. This study clearly shows the importance of multi-wavelength polarimetry at submillimeter bands to understand the dust properties of molecular clouds and the relationship between magnetic field and star formation.

arXiv commentMain article: 18 pages, 11 figures. Online supplemental material: 2 pages, 3 figures

References in corpus (42)

• Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC
• From filamentary clouds to prestellar cores to the stellar IMF: Initial highlights from the Herschel Gould Belt survey
• Herschel view of the Taurus B211/3 filament and striations: Evidence of filamentary growth?
• SCUBA-2: The 10000 pixel bolometer camera on the James Clerk Maxwell Telescope
• Radiative torques: Analytical Model and Basic Properties
• Planck intermediate results. XXXV. Probing the role of the magnetic field in the formation of structure in molecular clouds
• The global dust SED: Tracing the nature and evolution of dust with DustEM
• The APOGEE-2 Survey of the Orion Star Forming Complex II: Six-dimensional structure
• SCUBA-2: iterative map-making with the Sub-Millimetre User Reduction Facility
• Early Science with SOFIA, the Stratospheric Observatory for Infrared Astronomy
• SCUBA-2: on-sky calibration using submillimetre standard sources
• Millimeter-wave polarization of protoplanetary disks due to dust scattering
• First Observations of the Magnetic Field Geometry in Pre-stellar Cores
• The Efficiency of Grain Alignment in Dense Interstellar Clouds: A Reassessment of Constraints from Near Infrared Polarization
• The JCMT Gould Belt Survey: First results from the SCUBA-2 observations of the Ophiuchus molecular cloud and a virial analysis of its prestellar core population
• A unified model of grain alignment: radiative alignment of interstellar grains with magnetic inclusions
• First results from BISTRO -- a SCUBA-2 polarimeter survey of the Gould Belt
• Radiative grain alignment in protoplanetary disks: Implications for polarimetric observations
• The Herschel and JCMT Gould Belt Surveys: Constraining Dust Properties in the Perseus B1 Clump with PACS, SPIRE, and SCUBA-2
• Properties of the dense core population in Orion B as seen by the Herschel Gould Belt survey
• HAWC+/SOFIA Multiwavelength Polarimetric Observations of OMC-1
• Grain alignment induced by radiative torques: effects of internal relaxation of energy and complex radiation fields
• On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
• Dust models compatible with Planck intensity and polarization data in translucent lines of sight
• Grain Alignment in Starless Cores
• Dust Polarization Toward Embedded Protostars in Ophiuchus with ALMA. III. Survey Overview
• New Results on the Submillimeter Polarization Spectrum of the Orion Molecular Cloud
• JCMT BISTRO Survey observations of the Ophiuchus Molecular Cloud: Dust grain alignment properties inferred using a Ricean noise model
• Condition for the formation of micron-sized dust grains in dense molecular cloud cores
• Low-temperature MIR to submillimeter mass absorption coefficient of interstellar dust analogues II: Mg and Fe-rich amorphous silicates
• Polarization Properties and Magnetic Field Structures in the High-Mass Star-Forming Region W51 Observed with ALMA
• The far-infrared polarization spectrum of Rho Ophiuchi A from HAWC+/SOFIA observations
• Submillimeter Polarization of Galactic Clouds: A Comparison of 350 micron and 850 micron Data
• Millimeter-sized grains in the protostellar envelopes: where do they come from?
• Submillimeter Polarization Spectrum in the Vela C Molecular Cloud
• Dust spectrum and polarisation at 850 um in the massive IRDC G035.39-00.33
• Self-scattering of non-spherical dust grains
• The JCMT BISTRO Survey: An 850/450$\mu$m Polarization Study of NGC 2071IR in OrionB
• The JCMT Gould Belt Survey: SCUBA-2 Data-Reduction Methods and Gaussian Source Recovery Analysis
• Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region
• Polarization of Thermal Emission from Aligned Dust Grains Under an Anisotropic Radiation Field
• SOFIA Community Science I: HAWC+ Polarimetry of 30 Doradus

Cited by in corpus (8)

• The JCMT BISTRO Survey: A Spiral Magnetic Field in a Hub-filament Structure, Monoceros R2
• The JCMT BISTRO-2 Survey: Magnetic Fields of the Massive DR21 Filament
• Physical Modeling of Dust Polarization from Magnetically Enhanced Radiative Torque (MRAT) Alignment in Protostellar Cores with POLARIS
• Probing Three-Dimensional Magnetic Fields: I -- Polarized Dust Emission
• Understanding the Multi-wavelength Thermal Dust Polarisation from the Orion Molecular Cloud in Light of the Radiative Torque Paradigm
• The origin of dust polarization in the Orion Bar
• Alignment and Rotational Disruption of Dust Grains in the Galactic Centre Revealed by Polarized Dust Emission
• Limitations of the modified blackbody fit method for determining molecular cloud properties