Unveiling polarized emission from interstellar dust of the Large Magellanic Cloud with Planck

Abstract

Polarization of interstellar dust emission is a powerful probe of dust properties and magnetic field structure. Yet studies of external galaxies are hampered by foreground dust contribution. The aim of this study is to separate the polarised signal from the Large Magellanic Cloud (LMC) from that of the Milky Way (MW) in order to construct a wide-field, spatially complete map of dust polarization using the Planck 353 GHz data. To estimate the foreground polarization direction, we used velocity gradients in HI spectral line data and assessed the performance of the output by comparing to starlight extinction polarization. We estimate the foreground intensity using dust properties derived previously from the Planck data and we assume the foreground polarization to be uniform and equal to the average of the MW around the galaxy. After foreground removal, the geometry of the plane-of-the-sky magnetic field in the LMC tends to follow the structure of the atomic gas in the LMC. This is notably the case along the molecular ridges extending south and south-east of the 30 Doradus star-forming complex, and along more diffuse southern arm extending towards the Small Magellanic Cloud. There is also an alignment between the magnetic field and the outer arm in the western part. The median polarization fraction in the LMC is slightly lower than that observed for the MW while the anti-correlation between the polarization angle dispersion function and the polarization fraction is slightly larger. Overall, polarization fraction distribution is similar to that observed in the MW.

arXiv comment15 pages, 22 figures

References in corpus (55)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Gaia mission
• Interstellar Dust Grains
• The SIMBAD astronomical database
• Estimating distances from parallaxes IV: Distances to 1.33 billion stars in Gaia Data Release 2
• Planck 2018 results. I. Overview and the cosmological legacy of Planck
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• Reconnection in a Weakly Stochastic Field
• Planck 2013 results. XI. All-sky model of thermal dust emission
• The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time
• Planck Early Results: The Planck mission
• Planck 2018 results. IV. Diffuse component separation
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• Planck intermediate results. XXXV. Probing the role of the magnetic field in the formation of structure in molecular clouds
• Velocity Modification of HI Power Spectrum
• GASS: The Parkes Galactic All-Sky Survey. I. Survey Description, Goals, and Initial Data Release
• Dispersion of Magnetic Fields in Molecular Clouds. I
• The Second Survey of the Molecular Clouds in the Large Magellanic Cloud by NANTEN I: Catalog of Molecular Clouds
• Photo-astrometric distances, extinctions, and astrophysical parameters for Gaia DR2 stars brighter than G = 18
• A New Look at the Large-Scale HI Structure of the LMC
• Magnetically Aligned HI Fibers and the Rolling Hough Transform
• The global gas and dust budget of the Large Magellanic Cloud: AGB stars and supernovae, and the impact on the ISM evolution
• Placing Confidence Limits on Polarization Measurements
• The magnetic field of the Large Magellanic Cloud revealed through Faraday rotation
• Dust and Gas in the Magellanic Clouds from the HERITAGE Herschel Key Project. I. Dust Properties and Insights into the Origin of the Submm Excess Emission
• Revealing the cold dust in low-metallicity environments: I - Photometry analysis of the Dwarf Galaxy Survey with Herschel
• Foreground component separation with generalised ILC
• GASS: The Parkes Galactic All-Sky Survey. Update: improved correction for instrumental effects and new data release
• Planck Early Results: Origin of the submm excess dust emission in the Magellanic Clouds
• Velocity centroids as tracers of the turbulent velocity statistics
• Velocity Gradients as a Tracer for Magnetic Fields
• Tracing magnetic fields with spectroscopic channel maps
• The Generation of Magnetic Fields Through Driven Turbulence
• Subsonic Mechanical Alignment of Irregular Grains
• Velocity Spectrum for HI at High Latitudes
• Mapping the Magnetic Interstellar Medium in Three Dimensions Over the Full Sky with Neutral Hydrogen
• Tracing interstellar magnetic field using velocity gradient technique: Application to Atomic Hydrogen data
• Using dust, gas and stellar mass selected samples to probe dust sources and sinks in low metallicity galaxies
• Magnetic Field Strength Maps for Molecular Clouds: A New Method Based on a Polarization - Intensity Gradient Relation
• Magnetic Field Structure of the Large Magellanic Cloud from Faraday Rotation Measures of Diffuse Polarized Emission
• The Submm and mm Excess of the SMC: Magnetic Dipole Emission from Magnetic Nanoparticles?
• Magnetic Field Morphology in Interstellar Clouds with the Velocity Gradient Technique
• On the formation of density filaments in the turbulent interstellar medium
• Polarization measurements analysis I. Impact of the full covariance matrix on polarization fraction and angle measurements
• Bayesian analysis of polarization measurements
• Technique for separating velocity and density contributions in spectroscopic data and its application to studying turbulence and magnetic fields
• Magellanic Mayhem: Metallicities and Motions
• Statistical analysis of the interplay between magnetic fields and filaments hosting Planck Galactic Cold Clumps
• Producing Synthetic Maps of Dust Polarization using Velocity Channel Gradient Technique
• Velocity Gradients: Magnetic Field Tomography towards the Supernova Remnant W44
• Large-scale magnetic field in the Monoceros OB-1 East molecular cloud
• Polarised emission from aligned dust grains in nearby galaxies: predictions from the Auriga simulations
• Polarization measurement analysis III. Analysis of the polarization angle dispersion function with high precision polarization data
• The Magnetic Field Structure of the LMC 2 Supershell: NGC 2100
• Near-Infrared Polarization Source Catalog of the Northeastern Regions of the Large Magellanic Cloud

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