Column density toward GMF41. These maps show the column densities of atomic hydrogen traced by H I emission, the cold hydrogen gas traced by HISA, and molecular hydrogen traced by ¹³CO emission, respectively. The column densities are integrated over the velocity range of the filament region given in Table 1. The white contours in both panels show the integrated MWISP ¹³CO emission at the levels 6.0, 12.0, 24.0, and 34.0 K km s⁻¹. Left panel: H I column density traced by H I emission. Middle panel: HISA column density. Right panel: H₂ column density traced by ¹³CO.