Feedback timescale measured based on 21 μm emission versus feedback timescale measured based on Hα. The color bar shows the Hubble morphological type from the HyperLEDA database (Paturel et al. 2003a,b; Makarov et al. 2014). The dotted line shows the 1:1 relation. The obscured feedback phase traced by 21 μm (t_{fb, 21 μm} – t_{fb,  Hα}) is less than 4 Myr in all the galaxies from our sample, as shown by the plain black line, and less than 1 Myr for 28 out of 37 galaxies, as shown by the shaded area. We display the Spearman correlation coefficient as well as the log p-value of the data, excluding upper limits.