Top panel: three-dimensional local star formation efficiency, ϵ_3D, as a function of radius r (Eq. (22)) for different density indices p₀ (see key in bottom panel). The progenitor clump of the star-forming region is the same as previously, i.e. M₀ = 10⁴   M_⊙, R = 6   pc, and ϵ_ff = 0.1. The time elapsed since the onset of star-formation is t = 2 Myr. Bottom panel: same for the two-dimensional star formation efficiency, ϵ_2D, as a function of projected radius s (Eq. (23)).