Upper left: radial profiles (in units of HLR) of the star formation rate surface density (Σ_SFR), averaged in seven morphology bins. The horizontal line at 5 M_⊙Gyr^-1pc^-2 indicates the average Σ_SFR in the Milky Way (MW). Only the locations where the light fraction due to young populations is higher than 3.4% are included. Error bars show the dispersion (not the uncertainty) in log Σ_SFR for all the spirals (black) and for Sb galaxies (green). Other panels: for each Hubble type, solid, dashed, and dotted lines show the mean profiles obtained by excluding x_Y< 3.4%, W_Hα< 3Å, and W_Hα< 6Å, respectively. The gray-dashed lines show ⟨ Σ_SFR(R) ⟩ _cosmic profiles, the SFR surface density profiles obtained assuming a constant rate of star formation throughout the Hubble time.