Evolution of the v5blb perturbation. Top row: cross-sections of the v5blb model’s ecliptic plane at Δt ∈ {0, 1, 2.5, 4, 6} × 4.4828 kyr after injecting the perturbation in the absolute speed (log(u [km s⁻¹]), left panel) and in the number density (log(n [cm⁻³]), four right panels; distances in pc). The white arrow in the left panel indicates the movement direction of the perturbation with respect to the surrounding ISM. Centre row: synthetic observations of the above models in Hα [erg cm⁻² s⁻¹ sr⁻¹] at a distanceof 617 pc, face-on to the ecliptic (angular extent in degrees). The colour scale has been truncated at the bottom end; values below the minimum threshold are not displayed. Bottom row: synthetic observations of the same configuration in 70 μm dust emission [Jy sr⁻¹]. The solid angle per pixel is 5.07 × 10⁻⁸ sr.