Proton column density in the velocity interval between 50 and 70 km s⁻¹. We show the contributions from the molecular gas (left panel, contour level 2 × 10²² cm⁻², σ_rms = 2.2 × 10²⁰ cm⁻²) and the neutral gas (middle panel, contour level 4 × 10²¹ cm⁻², σ_rms = 1.2 × 10¹⁹ cm⁻²). The total column density is shown in the right panel (contour levels 1.5, 2.0, and 2.7 × 10²² cm⁻²). The color scale is expressed in cm⁻². Equatorial (J2000) coordinates are shown in the left panel.