Mass surface density map. The map shows the H I mass surface density integrated over the velocity interval − 57.5 < v_LSR < −48.5 km s⁻¹. The dashed contour gives the 5σ level at 2.3 M_⊙ pc⁻² by which the diffuse mass is calculated. The white contours show the mass surface densities at the levels 4.2 and 5.6 M_⊙ pc⁻², respectively.The spine of Maggie is color-coded by the centroid velocity shown in Fig. 9. The crosses mark the positions of the continuum sources listed in Table 1. The cyan crosses indicate the positions of absorption detections.