Dust optical depth τ₃₅₃ at 353 GHz in Galactic coordinates towards the Eridu (top) and Reticulum (bottom) filaments. The black lines give the orientation of the plane-of-the-sky B_sky magnetic field inferred from the dust polarisation observations at 353 GHz and at an angular resolution of 14′ (FWHM). The red contours delineate the filaments at HI gas column densities of 3 × 10²⁰ cm⁻² and 1.2 × 10²⁰ cm⁻², respectively.