Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds
Abstract
ABSTRACT It is well known that the polarized continuum emission from magnetically aligned dust grains is determined to a large extent by local magnetic field structure. However, the observed significant anticorrelation between polarization fraction and column density may be strongly affected, perhaps even dominated by variations in grain alignment efficiency with local conditions, in contrast to standard assumptions of a spatially homogeneous grain alignment efficiency. Here we introduce a generic way to incorporate heterogeneous grain alignment into synthetic polarization observations of molecular clouds (MCs), through a simple model where the grain alignment efficiency depends on the local gas density as a power law. We justify the model using results derived from radiative torque alignment theory. The effects of power-law heterogeneous alignment models on synthetic observations of simulated MCs are presented. We find that the polarization fraction-column density correlation can be brought into agreement with observationally determined values through heterogeneous alignment, though there remains degeneracy with the relative strength of cloud-scale magnetized turbulence and the mean magnetic field orientation relative to the observer. We also find that the dispersion in polarization angles-polarization fraction correlation remains robustly correlated despite the simultaneous changes to both observables in the presence of heterogeneous alignment.
- Authors:
-
[1];
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA, Lawrence Livermore National Laboratory, Livermore, CA 94550, USA
- Department of Astronomy, University of Virginia, Charlottesville, VA 22904, USA
- National Radio Astronomy Observatory, Charlottesville, VA 22903, USA
- Publication Date:
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 1572435
- Grant/Contract Number:
- AC52-07NA27344; LLNL-JRNL-764043
- Resource Type:
- Published Article
- Journal Name:
- Monthly Notices of the Royal Astronomical Society
- Additional Journal Information:
- Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 490 Journal Issue: 2; Journal ID: ISSN 0035-8711
- Publisher:
- Oxford University Press
- Country of Publication:
- United Kingdom
- Language:
- English
Citation Formats
King, Patrick K., Chen, Che-Yu, Fissel, L. M., and Li, Zhi-Yun. Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds. United Kingdom: N. p., 2019.
Web. doi:10.1093/mnras/stz2628.
King, Patrick K., Chen, Che-Yu, Fissel, L. M., & Li, Zhi-Yun. Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds. United Kingdom. doi:10.1093/mnras/stz2628.
King, Patrick K., Chen, Che-Yu, Fissel, L. M., and Li, Zhi-Yun. Sat .
"Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds". United Kingdom. doi:10.1093/mnras/stz2628.
@article{osti_1572435,
title = {Effects of grain alignment efficiency on synthetic dust polarization observations of molecular clouds},
author = {King, Patrick K. and Chen, Che-Yu and Fissel, L. M. and Li, Zhi-Yun},
abstractNote = {ABSTRACT It is well known that the polarized continuum emission from magnetically aligned dust grains is determined to a large extent by local magnetic field structure. However, the observed significant anticorrelation between polarization fraction and column density may be strongly affected, perhaps even dominated by variations in grain alignment efficiency with local conditions, in contrast to standard assumptions of a spatially homogeneous grain alignment efficiency. Here we introduce a generic way to incorporate heterogeneous grain alignment into synthetic polarization observations of molecular clouds (MCs), through a simple model where the grain alignment efficiency depends on the local gas density as a power law. We justify the model using results derived from radiative torque alignment theory. The effects of power-law heterogeneous alignment models on synthetic observations of simulated MCs are presented. We find that the polarization fraction-column density correlation can be brought into agreement with observationally determined values through heterogeneous alignment, though there remains degeneracy with the relative strength of cloud-scale magnetized turbulence and the mean magnetic field orientation relative to the observer. We also find that the dispersion in polarization angles-polarization fraction correlation remains robustly correlated despite the simultaneous changes to both observables in the presence of heterogeneous alignment.},
doi = {10.1093/mnras/stz2628},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 2,
volume = 490,
place = {United Kingdom},
year = {2019},
month = {9}
}
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DOI: 10.1093/mnras/stz2628
DOI: 10.1093/mnras/stz2628
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Works referenced in this record:
Polarization of Dust Emission in Clumpy Molecular Clouds and Cores
journal, July 2007
- Bethell, T. J.; Chepurnov, A.; Lazarian, A.
- The Astrophysical Journal, Vol. 663, Issue 2
The formation of massive molecular filaments and massive stars triggered by a magnetohydrodynamic shock wave
journal, October 2017
- Inoue, Tsuyoshi; Hennebelle, Patrick; Fukui, Yasuo
- Publications of the Astronomical Society of Japan, Vol. 70, Issue SP2
Theory of Star Formation
journal, September 2007
- McKee, Christopher F.; Ostriker, Eve C.
- Annual Review of Astronomy and Astrophysics, Vol. 45, Issue 1
Grain Alignment by Radiation in Dark Clouds and Cores
journal, September 2005
- Cho, Jungyeon; Lazarian, A.
- The Astrophysical Journal, Vol. 631, Issue 1
Simulations of polarized dust emission
journal, October 2006
- Pelkonen, V. -M.; Juvela, M.; Padoan, P.
- Astronomy & Astrophysics, Vol. 461, Issue 2
Fantastic Striations and Where to Find Them: The Origin of Magnetically Aligned Striations in Interstellar Clouds
journal, October 2017
- Chen, Che-Yu; Li, Zhi-Yun; King, Patrick K.
- The Astrophysical Journal, Vol. 847, Issue 2
Formation of Magnetized Prestellar Cores with Ambipolar Diffusion and Turbulence
journal, March 2014
- Chen, Che-Yu; Ostriker, Eve C.
- The Astrophysical Journal, Vol. 785, Issue 1
Modelling dust polarization observations of molecular clouds through MHD simulations
journal, December 2017
- King, Patrick K.; Fissel, Laura M.; Chen, Che-Yu
- Monthly Notices of the Royal Astronomical Society, Vol. 474, Issue 4
Infrared polarimetry and the Galactic magnetic field. II - Improved models
journal, April 1992
- Jones, Terry J.; Klebe, Dimitri; Dickey, John M.
- The Astrophysical Journal, Vol. 389
MAGNETIC FIELD COMPONENTS ANALYSIS OF THE SCUPOL 850 μm POLARIZATION DATA CATALOG
journal, October 2013
- Poidevin, Frédérick; Falceta-Gonçalves, Diego; Kowal, Grzegorz
- The Astrophysical Journal, Vol. 777, Issue 2
A new method to trace three-dimensional magnetic field structure within molecular clouds using dust polarization
journal, March 2019
- Chen, Che-Yu; King, Patrick K.; Li, Zhi-Yun
- Monthly Notices of the Royal Astronomical Society, Vol. 485, Issue 3
Filaments and ridges in Vela C revealed by Herschel : from low-mass to high-mass star-forming sites
journal, September 2011
- Hill, T.; Motte, F.; Didelon, P.
- Astronomy & Astrophysics, Vol. 533
Athena: A New Code for Astrophysical MHD
journal, September 2008
- Stone, James M.; Gardiner, Thomas A.; Teuben, Peter
- The Astrophysical Journal Supplement Series, Vol. 178, Issue 1
Density, Velocity, and Magnetic Field Structure in Turbulent Molecular Cloud Models
journal, January 2001
- Ostriker, Eve C.; Stone, James M.; Gammie, Charles F.
- The Astrophysical Journal, Vol. 546, Issue 2
Anisotropic Formation of Magnetized Cores in Turbulent Clouds
journal, September 2015
- Chen, Che-Yu; Ostriker, Eve C.
- The Astrophysical Journal, Vol. 810, Issue 2
Magnetic Fields in Molecular Clouds
journal, September 2012
- Crutcher, Richard M.
- Annual Review of Astronomy and Astrophysics, Vol. 50, Issue 1
Density Studies of mhd Interstellar Turbulence: Statistical Moments, Correlations and Bispectrum
journal, March 2009
- Burkhart, Blakesley; Falceta-Gonçalves, D.; Kowal, G.
- The Astrophysical Journal, Vol. 693, Issue 1
SILCC-Zoom: Polarization and depolarization in molecular clouds
journal, October 2018
- Seifried, D.; Walch, S.; Reissl, S.
- Monthly Notices of the Royal Astronomical Society, Vol. 482, Issue 2
On the radiation driven alignment of dust grains: Detection of the polarization hole in a starless core
journal, September 2014
- Alves, F. O.; Frau, P.; Girart, J. M.
- Astronomy & Astrophysics, Vol. 569
Polarized Submillimeter Emission from Filamentary Molecular Clouds
journal, December 2000
- Fiege, Jason D.; Pudritz, Ralph E.
- The Astrophysical Journal, Vol. 544, Issue 2
A Primer on Far‐Infrared Polarimetry
journal, September 2000
- Hildebrand, R. H.; Davidson, J. A.; Dotson, J. L.
- Publications of the Astronomical Society of the Pacific, Vol. 112, Issue 775
Exploring Magnetic Field Structure in Star-Forming Cores with Polarization of Thermal dust Emission
journal, November 2012
- Kataoka, Akimasa; Machida, Masahiro N.; Tomisaka, Kohji
- The Astrophysical Journal, Vol. 761, Issue 1
Planck intermediate results. XX. Comparison of polarized thermal emission from Galactic dust with simulations of MHD turbulence
journal, April 2015
- Ade, P. A. R.; Aghanim, N.; Alina, D.
- Astronomy & Astrophysics, Vol. 576
Balloon-Borne Submillimeter Polarimetry of the vela c Molecular Cloud: Systematic Dependence of Polarization Fraction on Column Density and Local Polarization-Angle Dispersion
journal, June 2016
- Fissel, Laura M.; Ade, Peter A. R.; Angilè, Francesco E.
- The Astrophysical Journal, Vol. 824, Issue 2
The size distribution of interstellar grains
journal, October 1977
- Mathis, J. S.; Rumpl, W.; Nordsieck, K. H.
- The Astrophysical Journal, Vol. 217
An application of an optimal statistic for characterizing relative orientations
journal, October 2017
- Jow, Dylan L.; Hill, Ryley; Scott, Douglas
- Monthly Notices of the Royal Astronomical Society, Vol. 474, Issue 1
Magnetic Fields in Star‐forming Molecular Clouds. II. The Depolarization Effect in the OMC‐3 Filament of Orion A
journal, November 2001
- Matthews, Brenda C.; Wilson, Christine D.; Fiege, Jason D.
- The Astrophysical Journal, Vol. 562, Issue 1
Cold Dark Clouds: The Initial Conditions for Star Formation
journal, September 2007
- Bergin, Edwin A.; Tafalla, Mario
- Annual Review of Astronomy and Astrophysics, Vol. 45, Issue 1
Studies of Regular and Random Magnetic Fields in the ISM: Statistics of Polarization Vectors and the Chandrasekhar‐Fermi Technique
journal, May 2008
- Falceta‐Gonçalves, Diego; Lazarian, Alex; Kowal, Grzegorz
- The Astrophysical Journal, Vol. 679, Issue 1
Matplotlib: A 2D Graphics Environment
journal, January 2007
- Hunter, John D.
- Computing in Science & Engineering, Vol. 9, Issue 3
The relation between the column density structures and the magnetic field orientation in the Vela C molecular complex
journal, July 2017
- Soler, J. D.; Ade, P. A. R.; Angilè, F. E.
- Astronomy & Astrophysics, Vol. 603
Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
journal, April 2015
- Ade, P. A. R.; Aghanim, N.; Alina, D.
- Astronomy & Astrophysics, Vol. 576
Interstellar Dust Grain Alignment
journal, August 2015
- Andersson, B-G; Lazarian, A.; Vaillancourt, John E.
- Annual Review of Astronomy and Astrophysics, Vol. 53, Issue 1
Magnetic Fields in Spiral Arms.
journal, July 1953
- Chandrasekhar, S.; Fermi, E.
- The Astrophysical Journal, Vol. 118
Change of Magnetic Field-Gas Alignment at the Gravity-Driven AlfvÉNic Transition in Molecular Clouds: Implications for dust Polarization Observations
journal, September 2016
- Chen, Che-Yu; King, Patrick K.; Li, Zhi-Yun
- The Astrophysical Journal, Vol. 829, Issue 2
Formation of Massive Molecular Cloud Cores by Cloud-Cloud Collision
journal, August 2013
- Inoue, Tsuyoshi; Fukui, Yasuo
- The Astrophysical Journal, Vol. 774, Issue 2
Dispersion of Magnetic Fields in Molecular Clouds. i
journal, April 2009
- Hildebrand, Roger H.; Kirby, Larry; Dotson, Jessie L.
- The Astrophysical Journal, Vol. 696, Issue 1
Predictions of polarized dust emission from interstellar clouds: spatial variations in the efficiency of radiative torque alignment
journal, June 2009
- Pelkonen, V. -M.; Juvela, M.; Padoan, P.
- Astronomy & Astrophysics, Vol. 502, Issue 3
Infrared polarimetry and the interstellar magnetic field
journal, November 1989
- Jones, Terry Jay
- The Astrophysical Journal, Vol. 346
The NumPy Array: A Structure for Efficient Numerical Computation
journal, March 2011
- van der Walt, Stéfan; Colbert, S. Chris; Varoquaux, Gaël
- Computing in Science & Engineering, Vol. 13, Issue 2
Grain Alignment in Starless Cores
journal, December 2014
- Jones, T. J.; Bagley, M.; Krejny, M.
- The Astronomical Journal, Vol. 149, Issue 1
yt: A MULTI-CODE ANALYSIS TOOLKIT FOR ASTROPHYSICAL SIMULATION DATA
journal, December 2010
- Turk, Matthew J.; Smith, Britton D.; Oishi, Jeffrey S.
- The Astrophysical Journal Supplement Series, Vol. 192, Issue 1
Dense core Formation in Supersonic Turbulent Converging Flows
journal, February 2011
- Gong, Hao; Ostriker, Eve C.
- The Astrophysical Journal, Vol. 729, Issue 2
Interstellar Turbulence I: Observations and Processes
journal, September 2004
- Elmegreen, Bruce G.; Scalo, John
- Annual Review of Astronomy and Astrophysics, Vol. 42, Issue 1
Infrared extinction and polarization due to partially aligned spheroidal grains - Models for the dust toward the BN object
journal, March 1985
- Lee, H. M.; Draine, B. T.
- The Astrophysical Journal, Vol. 290
An Imprint of Molecular Cloud Magnetization in the Morphology of the dust Polarized Emission
journal, August 2013
- Soler, J. D.; Hennebelle, P.; Martin, P. G.
- The Astrophysical Journal, Vol. 774, Issue 2