Total H I column density image of HIJASS J1021+6842 (corrected for primary beam attenuation). The field size is identical to that of Fig. 1. The beam size (﹩60^{\prime \prime }\times 52^{\prime \prime }﹩) is indicated in the lower left. Contours are plotted at 4, 7, 10, 13, and ﹩16\times 10^{19}﹩ atoms cm⁻². The total H I mass is ﹩1.5\times 10^{8}﹩ M_⊙. The boxes in the right‐hand panel indicate regions with coherent structures in position‐velocity space. Masses for the individual regions are as follows (in units of 10⁷ M_⊙): I = 1.3; II = 2.6; III = 0.8; IV = 4.1; V = 1.5; VI = 3.0; VII = 1.1. The numbers adjacent to the boxes give the velocities at which the individual regions appear brightest in the channel maps. Note an apparent gradient in velocity ranging from around 70 km s⁻¹ (region I) to −50 km s⁻¹ (region VII).