Mid-IR SED for elliptical-type galaxies NGC 584, NGC 777, and M 87. The diagram includes 2MASS XSC, IRAC, MIPS, and WISE photometry, where the 2MASS isophotal radius and shape were used as the fiducial aperture. The NGC 584 spectra are from SINGS Spitzer/IRS (SL and LL modules) of the nucleus. There is no IRAC data for M 87. The blue and gray lines are old 13 and 5 Gyr galaxy models, respectively, adapted from the GRASIL code (Polletta et al. 2006, 2007; Silva et al. 1998) normalized to the near-IR.