As a function of stellar mass, g−i color for our sample of isolated elliptical (T ≤ −4) galaxies out to z = 0.08 (black filled squares). In addition, we include a sample of elliptical galaxies located in the Coma supercluster (red filled triangles). The red line shows Eq. (10) to separate red/blue galaxies. Blue filled squares and green filled squares show the blue and red isolated ellipticals, which are also star-forming galaxies according to Eq. (11), respectively. The numbers are the ID in the UNAM-KIAS catalog for the former. Magenta open squares correspond to the recently quenched elliptical (RQE) galaxies following the color-color criterion of Sect. 3.3. Top and right panels: normalized density distributions of stellar mass and g−i color for isolated elliptical galaxies (gray solid histogram) and elliptical galaxies located in the Coma supercluster (red open histogram), respectively. The integral of each histogram sums to unity.