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Planck 2018 results. XII. Galactic astrophysics using polarized dust emission

Aghanim, N. and Ghosh, T. and Bock, J. J. and Crill, B. P. and Doré, O. and Helou, G. and Rocha, G. and Chary, R.-R. (2018) Planck 2018 results. XII. Galactic astrophysics using polarized dust emission. . (Unpublished)

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We present 353 GHz full-sky maps of the polarization fraction p, angle ψ, and dispersion of angles S of Galactic dust thermal emission produced from the 2018 release of Planck data. We confirm that the mean and maximum of p decrease with increasing N_H. The uncertainty on the maximum polarization fraction, p_(max)=22.0% at 80 arcmin resolution, is dominated by the uncertainty on the zero level in total intensity. The observed inverse behaviour between p and S is interpreted with models of the polarized sky that include effects from only the topology of the turbulent Galactic magnetic field. Thus, the statistical properties of p, ψ, and S mostly reflect the structure of the magnetic field. Nevertheless, we search for potential signatures of varying grain alignment and dust properties. First, we analyse the product map S×p, looking for residual trends. While p decreases by a factor of 3--4 between N_H=10^(20) cm^(−2) and N_H=2×10^(22)cm^(−2), S×p decreases by only about 25%, a systematic trend observed in both the diffuse ISM and molecular clouds. Second, we find no systematic trend of S×p with the dust temperature, even though in the diffuse ISM lines of sight with high p and low S tend to have colder dust. We also compare Planck data with starlight polarization in the visible at high latitudes. The agreement in polarization angles is remarkable. Two polarization emission-to-extinction ratios that characterize dust optical properties depend only weakly on NH and converge towards the values previously determined for translucent lines of sight. We determine an upper limit for the polarization fraction in extinction of 13%, compatible with the p_(max) observed in emission. These results provide strong constraints for models of Galactic dust in diffuse gas.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Aghanim, N.0000-0002-6688-8992
Bock, J. J.0000-0002-5710-5212
Crill, B. P.0000-0002-4650-8518
Doré, O.0000-0002-5009-7563
Helou, G.0000-0003-3367-3415
Chary, R.-R.0000-0001-7583-0621
Additional Information:The Planck Collaboration acknowledges the support of ESA; CNES, and CNRS/INSU-IN2P3-INP (France); ASI, CNR, and INAF (Italy); NASA and DoE (USA); STFC and UKSA (UK); CSIC, MINECO, JA, and RES (Spain); Tekes, AoF, and CSC (Finland); DLR and MPG (Germany); CSA (Canada); DTU Space (Denmark); SER/SSO (Switzerland); RCN (Norway); SFI (Ireland); FCT/MCTES (Portugal); ERC and PRACE (EU). A description of the Planck Collaboration and a list of its members, indicating which technical or scientific activities they have been involved in, can be found at This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. The research leading to these results has received funding from the European Research Council under the European Union’s Horizon 2020 Research & Innovation Framework Programme / ERC grant agreement ERC-2016-ADG-742719. This research has received funding from the Agence Nationale de la Recherche (ANR-17-CE31-0022). We thank Pekka Teerikorpi and Andrei Berdyugin for kindly providing stellar polarization data and providing insights on stellar polarization references, Gina Panopoulou for discussions of the zero point calibration of the polarization angle, and Ralf Siebenmorgen and Nikolai Voshchinnikov for statistical discussions. We gratefully acknowledge the help of Rosine Lallement regarding the handling of the Gaia data.
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
European Space Agency (ESA)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Institut National des Sciences de l'Univers (INSU)UNSPECIFIED
Agenzia Spaziale Italiana (ASI)UNSPECIFIED
Consiglio Nazionale delle Ricerche (CNR)UNSPECIFIED
Istituto Nazionale di Astrofisica (INAF)UNSPECIFIED
Department of Energy (DOE)UNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
United Kingdom Space Agency (UKSA)UNSPECIFIED
Consejo Superior de Investigaciones Científicas (CSIC)UNSPECIFIED
Ministerio de Economía, Industria y Competitividad (MINECO)UNSPECIFIED
Junta de AndalucíaUNSPECIFIED
Spanish Supercomputing Network (RES)UNSPECIFIED
Finnish Ministry of Employment and the EconomyUNSPECIFIED
Academy of FinlandUNSPECIFIED
Finnish IT Center for Science (CSC)UNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)UNSPECIFIED
Max Planck SocietyUNSPECIFIED
Canadian Space Agency (CSA)UNSPECIFIED
State Secretariat for Education and Research (Switzerland) UNSPECIFIED
Swiss Space Office (SSO)UNSPECIFIED
Research Council of NorwayUNSPECIFIED
Science Foundation, IrelandUNSPECIFIED
Fundação para a Ciência e a Tecnologia (FCT)UNSPECIFIED
Ministério da Ciência, Tecnologia e Ensino Superior (MCTES)UNSPECIFIED
European Research Council (ERC)742719
Partnership for Advanced Computing in Europe (PRACE)UNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-17-CE31-0022
Subject Keywords:Polarization – Magnetic fields – Turbulence – ISM: dust – Galaxy: ISM – submillimetre: ISM
Record Number:CaltechAUTHORS:20190627-085435272
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:96767
Deposited By: Tony Diaz
Deposited On:27 Jun 2019 16:11
Last Modified:03 Oct 2019 21:25

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