The Galactic interstellar medium has a preferred handedness of magnetic misalignment

Understand

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.