FM18p.18 — Statistical properties of polarized dust emission : lessons from a model of the turbulent and magnetized interstellar medium

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Aug 10th at 6:00 PM until 6:00 PM

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Author(s): François Levrier1, Jérémy Neveu1

Institution(s): 1. LERMA/LRA, ENS Paris / Observatoire de Paris / UPMC

The Planck satellite has mapped the polarized microwave sky (from 30 GHz to 353 GHz) with unprecedented sensitivity and angular resolution. This wealth of data yields the first complete map of polarized thermal emission from dust in our own Galaxy, shedding new light on the Galactic magnetic field. Within this data lie clues to the statistical properties of its turbulent component, in particular its spectral index across spatial scales. To extract these properties, a thorough understanding of how they translate into those of the polarized emission maps is necessary. We address this problem using a model of the turbulent and magnetized interstellar medium based on fractional Brownian motion fields. I will present simulated maps of polarized dust emission (Stokes Q and U) and show how various statistical observables depend on the model parameters. Within the framework of this model, I will show that the polarization angle dispersion function $\Delta \Psi$ is unambiguously linked to the magnetic field spectral index, independently of the dust statistical distribution.