Angular wavelet power spectra of pitch angles ϕ on the scale 2a = 1′ normalized to unit maximum: the pitch angles ϕ_m of the structures of the polarized intensity P6 (black dotted), neutral gas (green), and CO (blue dashed). The spectrum of the pitch angles ϕ_p of the magnetic field vectors defined in Eq. (8) is shown with the red dot-dashed curve. The pitch angles are measured clockwise from the tangent to the local circumference on the sky plane. The upper panel shows the spectra for the whole galaxy, while the lower panel shows them for the region of spiral arms (i.e. with the bar region excluded).