HectoMAP gal. single-Sersic mod. struct. param.

The combined evidence supports inside-out quenching as the dominant mechanism halting star formation during this epoch. The normalization of the size - stellar mass relation (the typical size of a M*~10^11^M_{sun}_ quiescent galaxy) increases by ~30% between z~0.6 and z~0.2 in the red rest-frame and remains constant in the rest-frame UV. Size growth is age-independent; newcomers are ~20% larger than the aging population across redshifts and rest-frames.

Based on the Sersic index - stellar mass relation in the UV, M*~10^11^M_{sun}_ quiescent galaxies maintain a constant central concentration (n~4 for the aging population and n~2 for newcomers). In the red rest-frame, both subpopulations have de Vaucouleurs profiles after accounting for selection effects. The larger sizes and disk-like UV profiles of newcomers link them to their direct progenitors in the star-forming population.

For the aging population, the steady red rest-frame growth and elevated central concentration in both red and UV rest-frames suggest minor mergers with progressively redder satellites at lower redshifts as the primary driver of galaxy evolution in the quiescent phase. Large samples of low surface brightness galaxies available in forthcoming sensitive large-area imaging surveys are ideal testbeds for this prediction.