Maps of the peak intensity for transitions near 100 GHz. The left panel gives A_V as inferred from Herschel data. Contours at 5 and 30 mag are drawn and repeated in all panels, and the peak intensity is stated for every transition. Line emission maps are smoothed to resolution before filled contours are drawn at signal-to-noise ratios of 3, 5, 10, 30, 50, and 100. Panels are ordered by increasing critical density, n_cr.