We analysed a sample of 552 galaxies from the LEGA-C spectroscopic survey (0. 6 10^ 11 M_⊙ galaxies in general. Lower-mass star-forming galaxies instead have typically lower metallicities than their local counterparts, indicating significant enrichment since z in the low-mass regime. Notably, the median of the stellar ages of the general population and of quiescent galaxies has changed by only 2 Gyr between z=0. 7 and z=0. 1, which is less than expected from cosmic ageing. Some quiescent galaxies must evolve passively to reach the old boundary of the local population. In order to explain the evolution of the median trends, however, both individual evolution through rejuvenation and/or minor merging that affects the outer galaxy regions and population evolution through quenching of massive metal-rich star-forming galaxies are required.
Gallazzi et al. (Mon,) studied this question.