Evidence for Line-of-Sight Frequency Decorrelation of Polarized Dust Emission in $Planck$ Data

Abstract

If a single line of sight (LOS) intercepts multiple dust clouds of different spectral energy distributions and magnetic field orientations, the frequency scaling of each of the Stokes $Q$ and $U$ parameters of thermal dust emission may be different ("LOS frequency decorrelation"). We present first evidence for LOS frequency decorrelation in $Planck$ data. We use independent, neutral-hydrogen--measurements of the number of clouds per LOS and the magnetic field orientation in each cloud to select two sets of sightlines: (i) a target sample (pixels likely to exhibit LOS frequency decorrelation); (ii) a control sample (pixels lacking complex LOS structure). We test the null hypothesis that LOS frequency decorrelation is not detectable in $Planck$ 353 and 217~GHz polarization data at high Galactic latitudes. The data reject this hypothesis at high significance. The detection is robust against choice of CMB map and map-making pipeline. The observed change in polarization angle due to LOS frequency decorrelation is detectable above the $Planck$ noise level. The probability that the detected effect is due to noise alone ranges from $5\times 10^{-2}$ to $4\times 10^{-7}$, depending on the CMB subtraction algorithm and treatment of residual systematics; correcting for residual systematics increases the significance of the effect. The LOS decorrelation effect is stronger for sightlines with more misaligned magnetic fields, as expected. We estimate that an intrinsic variation of $\sim 15\%$ in the ratio of 353 to 217~GHz polarized emission between clouds is sufficient to reproduce the measured effect. Our finding underlines the importance of ongoing studies to map the 3D structure of the magnetized dusty ISM that could help component separation methods to account for frequency decorrelation effects in CMB polarization studies.

arXiv comment17 pages, 15 figures. Accepted for publication by A&A

References in corpus (47)

• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• HI4PI: A full-sky HI survey based on EBHIS and GASS
• The Simons Observatory: Science goals and forecasts
• Planck 2013 results. XI. All-sky model of thermal dust emission
• Extrapolation of Galactic Dust Emission at 100 Microns to CMBR Frequencies Using FIRAS
• Planck 2018 results. IV. Diffuse component separation
• Planck intermediate results. XIX. An overview of the polarized thermal emission from Galactic dust
• Planck 2018 results. III. High Frequency Instrument data processing and frequency maps
• The Quest for B Modes from Inflationary Gravitational Waves
• Planck intermediate results. LVII. Joint Planck LFI and HFI data processing
• Planck 2013 results. XII. Component separation
• Planck 2015 results. IX. Diffuse component separation: CMB maps
• The Optical-Infrared Extinction Curve and its Variation in the Milky Way
• Magnetically Aligned HI Fibers and the Rolling Hough Transform
• Planck intermediate results. XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes
• Planck Early Results XXIV: Dust in the diffuse interstellar medium and the Galactic halo
• Planck 2018 results. XI. Polarized dust foregrounds
• Planck 2018 results. XII. Galactic astrophysics using polarized dust emission
• Planck intermediate results. XXIX. All-sky dust modelling with Planck, IRAS, and WISE observations
• A new, large-scale map of interstellar reddening derived from HI emission
• The LiteBIRD Satellite Mission - Sub-Kelvin Instrument
• A novel estimator of the polarization amplitude from normally distributed Stokes parameters
• Neutral hydrogen structures trace dust polarization angle: Implications for cosmic microwave background foregrounds
• Rethinking CMB foregrounds: systematic extension of foreground parameterizations
• Mapping the Magnetic Interstellar Medium in Three Dimensions Over the Full Sky with Neutral Hydrogen
• Magnetically Dominated Strands of Cold Hydrogen in the Riegel-Crutcher Cloud
• Modeling Thermal Dust Emission with Two Components: Application to the Planck HFI Maps
• GHIGLS: HI mapping at intermediate Galactic latitude using the Green Bank Telescope
• An application of an optimal statistic for characterising relative orientations
• The Physical Nature of Neutral Hydrogen Intensity Structure
• SRoll2: an improved mapmaking approach to reduce large-scale systematic effects in the Planck High Frequency Instrument legacy maps
• Planck intermediate results. L. Evidence for spatial variation of the polarized thermal dust spectral energy distribution and implications for CMB $B$-mode analysis
• RoboPol: A four-channel optical imaging polarimeter
• Dust models post-Planck: constraining the far-infrared opacity of dust in the diffuse interstellar medium
• A 3-D model of polarised dust emission in the Milky Way
• Modelling and simulation of large-scale polarized dust emission over the southern Galactic cap using the GASS HI data
• Mitigating Complex Dust Foregrounds in Future CMB Polarization Experiments
• 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
• Extracting the cold neutral medium from HI emission with deep learning: Implications for Galactic foregrounds at high latitude
• Local Bubble contribution to the 353-GHz dust polarized emission
• Line-of-Sight Extrapolation Noise in Dust Polarization
• No evidence for dust B-mode decorrelation in Planck data
• Maps of the number of HI clouds along the line of sight at high galactic latitude
• Small-Scale HI Channel Map Structure is Cold: Evidence from Na I Absorption at High Galactic Latitudes
• A 3D model for CO molecular line emission as a potential CMB polarization contaminant
• Determining thermal dust emission from Planck HFI data using a sparse, parametric technique

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• BICEP / Keck XVI: Characterizing Dust Polarization through Correlations with Neutral Hydrogen
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• Improved Galactic Foreground Removal for B-Modes Detection with Clustering Methods
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• Characterizing line-of-sight variability of polarized dust emission with future CMB experiments
• Constraints on the Optical Depth to Reionization from Balloon-Borne CMB Measurements
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• The Simons Observatory: Assessing the Impact of Dust Complexity on the Recovery of Primordial $B$-modes
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• The effect of cosmic variance on the characteristics of dust polarization power spectra
• The WALOP-North Instrument I: Optical Design, Filter Design, Calibration
• A three-dimensional reconstruction of the interstellar magnetic field toward a star-forming region
• A new approach of estimating the Galactic thermal dust and synchrotron polarized emission template in the microwave bands