The Galactic interstellar medium has a preferred handedness of magnetic misalignment

Zhiqi Huang

Submitted on 30 June 2022


The Planck mission detected a positive correlation between the intensity (T) and B-mode polarization of the Galactic thermal dust emission. The TB correlation is a parity-odd signal, whose statistical mean vanishes in models with mirror symmetry. Recent work has shown with strong evidence that local handedness of the misalignment between the dust filaments and the sky-projected magnetic field produces TB signals. However, it remains unclear whether the observed global TB signal is caused by statistical fluctuations of magnetic misalignment angles, or whether some parity-violating physics in the interstellar medium sets a preferred misalignment handedness. The present work aims to make a quantitative statement about how confidently the statistical-fluctuation interpretation is ruled out by filament-based simulations of polarized dust emission. We use the publicly available DUSTFILAMENTS code to simulate the dust emission from filaments whose magnetic misalignment angles are symmetrically randomized, and construct the probability density function of ξp, a weighted sum of TB power spectrum. We find that Planck data has a 10σ tension with the simulated ξp distribution. Our results strongly support that the Galactic filament misalignment has a preferred handedness, whose physical origin is yet to be identified.


Comment: 6 pages, 3 figures

Subjects: Astrophysics - Astrophysics of Galaxies; Astrophysics - Cosmology and Nongalactic Astrophysics; General Relativity and Quantum Cosmology; High Energy Physics - Phenomenology; High Energy Physics - Theory; 83F05; J.2