W43-MM2&MM3 mini-starburst ridge traced by its column density (color scale), derived from the ALMA 1.3 mm continuum image of Pouteau et al. (2022). It hosts a rich cluster of 205 cores (gray crosses), as reported by Pouteau et al. (2022), and the UCHII region W43-MM3, which is traced by its H41α emission line (Galván-Madrid et al., in prep.; gray scale) and where the column density is not computed. Green polygons outline the W43-MM2&MM3 subregions defined in Sect. 2.2. The ellipse in the lower-left corner indicates the 0.46″ angular resolution of the column density image, while the scale bar indicates the length scale at a distance of 5.5 kpc. Panel a: dashed white boxes outline the zoomed-in views shown in panels b–c.