Can the observed E/B ratio for dust galactic foreground be explained by sub-Alfvenic turbulence?

Abstract

Recent Planck observations of dust polarization in the Galaxy have revealed that the power in $E$ mode is twice that in $B$ mode. Caldwell et. al. have formulated a theoretical model in the context of magnetohydrodynamic (MHD) turbulence and found it problematic to account for this result. In particular, they concluded that there is a very narrow range of theoretical parameters that could account for the observation. This poses a problem of whether the accepted description of MHD turbulence can apply to the interstellar medium. We revisit the problem and demonstrate that MHD turbulence corresponding to the high galactic latitudes range of Alfvén Mach numbers, i.e. $M_A\lesssim 0.5$, can successfully explain the available results for the $E$ to $B$ mode ratio.

Accepted to MNRAS Letters. 5 pages, 3 figures

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Cited by in corpus (1)

• Ambipolar diffusion in large Prandtl number turbulence