Separation of polarized dust emission in Planck observations with scattering transforms
Year: 2026
Type: article
Abstract: Context . Polarized dust emission is a major astrophysical foreground contaminant for the measurement of cosmic microwave background (CMB) polarization, which must be accurately measured to look for the faint primordial polarization B modes of inflationary origin. The best currently available maps, obtained from Planck space mission data, are noise-dominated in the high Galactic latitude regions that are most relevant for CMB observations. Aims . The goal of this work is to obtain better dust polarization maps from Planck observations, by exploiting both the dependence between polarization and total intensity, as well as the non-Gaussian filamentary structure of the dust emission. Methods . To this effect, we used scattering transforms, which provide a stable and interpretable representation of complex non-Gaussian textures, allowing for a data-driven analysis approach requiring no explicit priors on dust. The analysis was performed locally on Cartesian patches of sky, where Stokes linear polarization parameters, redefined in a local reference frame, were modeled as the sum of a signal of interest and a nuisance term. Using multiple realizations of the random nuisance term, we recovered the polarized dust maps by minimizing a composite objective function that enforces multiple statistical constraints in scattering space. Results . The proposed algorithm reconstructs maps of polarized dust emission whose statistics are consistent with those expected from the Planck data once random nuisance realizations are added. This was confirmed in a validation test using a high signal-to-noise sky region as a test case. Comparisons with existing dust polarization maps and models show that our approach better recovers small-scale polarized dust emission, and that our reconstructed power and cross-spectra closely match those of the dust polarization maps. A second set of maps that deterministically reproduce the features of the dust polarized emission is also produced.
Source: Astronomy and Astrophysics
Institutions: Centre National de la Recherche Scientifique, Université Paris Cité, Université Paris Sciences et Lettres, École Normale Supérieure - PSL, Sorbonne Université, Laboratoire de Physique de l'Ecole Normale Supérieure, Lawrence Berkeley National Laboratory, University of Chicago, Centre Pierre Binétruy, University of California, Berkeley
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,865
OpenAlex ID: W7162542009