XIIIth School of Cosmology
November 12 - 18, 2017IESC, Cargèse
The CMB from A to Z
promises and challenges of the CMB as a cosmological probe

Statistical characterization and modelling of Galactic foregrounds to CMB polarization

François Boulanger
Ecole Normale Supérieure, Paris


  1. Angular power spectra of Galactic foregrounds
  2. Frequency dependence of Galactic polarized emission
  3. Statistical simulations of the dust foreground to CMB polarization
  4. Forgerounds complexity: the interplay between dust, magnetic fields and the density structure of interstellar matter


The study of  Galactic foregrounds has become entwined with the analysis of the cosmic microwave background (CMB) polarization.  On the one hand, CMB data provide new insights on the physics of the magnetized interstellar medium (ISM), and on the other hand  the challenge of component separation binds the search for primordial B-modes to Galactic astrophysics. Their detection is a paramount objective of cosmology, but any claim will face a critical assessment against alternative interpretations involving foregrounds.
I will present the current knowledge and research directions at this interface between astrophysics and cosmology, where we seek to  characterize and model polarized foregrounds statistically to assess and optimize component separation.


  • Articles
    • Planck Collaboration 2015 A&A 576, 107: Planck intermediate results XXII: Frequency dependence of dust emission in intensity and
    • Planck Collaboration 2016 A&A 586, 133: Planck intermediate results. XXX. The angular power spectrum of polarized dust emission
      at intermediate and high Galactic latitudes.
    • Planck Collaboration 2016 A&A 586, 141: Planck intermediate results XXXVIII: E and B-modes of dust polarization from the magnetized filamentary structure of the interstellar.
    • Vansyngel, F., Boulanger, F., Ghosh, T. et al. 2017 A&A 603, A62, Statistical simulations of the dust foreground to CMB polarization.