Left panel: SFR vs EPG mass for our HALOGAS sample. Right panel: theoretical EPG mass predicted by a galactic fountain model (Eq. (11) with β = 7) vs that inferred from the data. The two panels span the same range (∼1.5 dex) on both axes. Error-bars are determined by assuming a 10% uncertainty on the distances and a 20% uncertainty on the total SFR, in addition to the uncertainty on the R_SFR discussed in the text. Interacting galaxies and systems with a poorly fit EPG are shown with separate symbols. We have also included NGC 891 (M_EPG from Marinacci et al. 2010a) and the Milky Way, for which we used M_EPG = 3.2 ± 1.0 × 10⁸ M_⊙ (MF11), and assumed fiducial values for SFR, R_SFR and v_flat of 2 ± 1 M_⊙ yr⁻¹, 2.5 ± 0.5 kpc and 240 ± 10 km s⁻¹ respectively.