An Imprint of the Galactic Magnetic Field in the Diffuse Unpolarized Dust Emission

Abstract

It is well known that aligned, aspherical dust grains emit polarized radiation and that the degree of polarization depends on the angle $\psi$ between the interstellar magnetic field and the line of sight. However, anisotropy of the dust absorption cross sections also modulates the $totalintensity$ of the radiation as the viewing geometry changes. We report a detection of this effect in the high Galactic latitude $Planck$ data, finding that the 353 GHz dust intensity per $N_{\mathrm{HI}}$ is smaller when the Galactic magnetic field is mostly in the plane of the sky and larger when the field is mostly along the line of sight. These variations are of opposite sign and roughly equal magnitude as the changes in polarized intensity per $N_{\mathrm{HI}}$ with $\psi$, as predicted. In principle, the variation in intensity can be used in conjunction with the dust polarization angle to constrain the full 3D orientation of the Galactic magnetic field.

arXiv commentSubmitted to ApJ

References in corpus (39)

• Astropy: A Community Python Package for Astronomy
• emcee: The MCMC Hammer
• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• IRIS: A new generation of IRAS maps
• BICEP2 / Keck Array x: Constraints on Primordial Gravitational Waves using Planck, WMAP, and New BICEP2/Keck Observations through the 2015 Season
• Planck 2018 results. IV. Diffuse component separation
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• GASS: The Parkes Galactic All-Sky Survey. I. Survey Description, Goals, and Initial Data Release
• Planck 2013 results. XXX. Cosmic infrared background measurements and implications for star formation
• Dispersion of Magnetic Fields in Molecular Clouds. I
• Dispersion of Magnetic Fields in Molecular Clouds. II
• Studies of regular and random magnetic fields in the ISM: statistics of polarization vectors and the Chandrasekhar-Fermi technique
• Planck intermediate results. XX. Comparison of polarized thermal emission from Galactic dust with simulations of MHD turbulence
• Foreground component separation with generalised ILC
• A new, large-scale map of interstellar reddening derived from HI emission
• First results from BISTRO -- a SCUBA-2 polarimeter survey of the Gould Belt
• Spatially Resolved Magnetic Field Structure in the Disk of a T Tauri Star
• Neutral hydrogen structures trace dust polarization angle: Implications for cosmic microwave background foregrounds
• Balloon-Borne Submillimeter Polarimetry of the Vela C Molecular Cloud: Systematic Dependence of Polarization Fraction on Column Density and Local Polarization-Angle Dispersion
• The Effelsberg-Bonn HI Survey (EBHIS)
• HAWC+/SOFIA Multiwavelength Polarimetric Observations of OMC-1
• Planck intermediate results. XXI. Comparison of polarized thermal emission from Galactic dust at 353 GHz with interstellar polarization in the visible
• First Detection of Polarization of the Submillimetre Diffuse Galactic Dust Emission by Archeops
• The Local Bubble: a magnetic veil to our Galaxy
• Extragalactic Imprints in Galactic Dust Maps
• Large-scale Maps of the Cosmic Infrared Background from Planck
• Practical Modeling of Large-Scale Galactic Magnetic Fields: Status and Prospects
• Quantum Suppression of Alignment in Ultrasmall Grains: Microwave Emission from Spinning Dust will be Negligibly Polarized
• A new probe of line-of-sight magnetic field tangling
• Demonstration of magnetic field tomography with starlight polarization towards a diffuse sightline of the ISM
• Modeling Dust Polarization Observations of Molecular Clouds through MHD Simulations
• PASIPHAE: A high-Galactic-latitude, high-accuracy optopolarimetric survey
• Local Bubble contribution to the 353-GHz dust polarized emission
• The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry-BLASTPol: Performance and results from the 2012 Antarctic flight
• Predicting CMB dust foreground using galactic 21 cm data

Cited by in corpus (10)

• Mapping the Magnetic Interstellar Medium in Three Dimensions Over the Full Sky with Neutral Hydrogen
• High-accuracy estimation of magnetic field strength in the interstellar medium from dust polarization
• The Origin of Parity Violation in Polarized Dust Emission and Implications for Cosmic Birefringence
• Using the Starlight Polarization Efficiency Integral to Constrain Shapes and Porosities of Interstellar Grains
• Maps of Magnetic Field Strength in the OMC-1 using HAWC+ FIR Polarimetric data
• Maps of the number of HI clouds along the line of sight at high galactic latitude
• Magnetic Misalignment of Interstellar Dust Filaments
• On the Shapes of Interstellar Grains: Modeling Extinction and Polarization by Spheroids and Continuous Distributions of Ellipsoids
• Full-sky, arcminute-scale, 3D models of Galactic microwave foreground dust emission based on filaments
• Why take the square root? An assessment of interstellar magnetic field strength estimation methods