L_X(gas)/L_SFR vs. L_X(gas)/L_K, for the mergers, the normal spirals, and the E/S0 galaxies. The mergers are color-coded by merger stage, after correcting for internal absorption. Merger stages 1 and 2 systems are marked as open green triangles. Merger stages 3, 4, and 5 are open cyan diamonds, and merger stages 6 and 7 are identified by blue open squares. Merging galaxies with a Seyfert nucleus are circled in red. Small dots of the same color represent the mergers with only Galactic absorption. Large black crosses mark the normal spirals after correction for internal absorption; small black dots are spirals with only Galactic absorption. The red open squares represent the Goulding et al. (2016) massive ellipticals and the Su et al. (2015) E/S0 galaxies are marked by magenta open circles, calculated using SFRs derived from the UV+IR data with the Hao et al. (2011) relation (these SFRs are assumed to be upper limits for the E/S0 galaxies). The magenta filled upside-down triangles mark the Su et al. (2015) E/S0 galaxies using SFRs from SED fitting. The black line is the relation expected if the observed 24 μm flux is powered solely by the older stellar population (see the text for more details). The E/S0 values were obtained using only Galactic absorption.