2016MNRAS.463.2296R

Recent observations have detected molecular outflows in a few nearby starburst nuclei. We discuss the physical processes at work in such an environment in order to outline a scenario that can explain the observed parameters of the phenomenon, such as the molecular mass, speed and size of the outflows. We show that outflows triggered by OB associations, with N_OB >= 10⁵ (corresponding to a star formation rate (SFR)>=1 M_☉ yr^–1 in the nuclear region), in a stratified disc with mid-plane density n₀ ∼ 200-1000 cm^–3 and scaleheight z₀ >= 200(n₀/10² cm^–3)^–3/5 pc, can form molecules in a cool dense and expanding shell. The associated molecular mass is >=10⁷ M_☉ at a distance of a few hundred pc, with a speed of several tens of km s^–1. We show that an SFR surface density of 10 <= Σ_SFR <= 50 M_☉ yr^–1 kpc^–2 favours the production of molecular outflows, consistent with observed values.