The differences between mass- and light-derived structural parameters
  over time for MaNGA Elliptical galaxies
  We apply stellar population synthesis analysis to obtain spatially-resolved
archaeological inferences for a large sample of "red and dead" Elliptical
galaxies (Classical Ellipticals; CLEs) from the MaNGA/SDSS-IV DR15 survey. From
their 2D stellar light and mass maps, we explore the differences between the
radial mass and light distributions in the rest-frame bands $g,$ $r,$ and $i$
as functions of look-back time, $t_{\rm lb}$, or redshift, $z$. We characterize
these differences through the ratios between the following mass- and
light-derived global properties: sizes, concentrations, and effective surface
densities. We find that the mass-to-light ratios of these properties change
with $t_{\rm lb}$, more the more massive the galaxies are. The CLE galaxy
archaeological progenitors are, on average, less compact, concentrated, and
dense in light than in mass as $z$ decreases. However, at later times, when
also the evolution of the progenitors becomes passive at all radii, there is an
upturn in these trends and the differences between mass and light in
compactness/concentration decrease towards $z\sim 0$. The trends in the ratios
of mass to light sizes agree qualitatively with results from direct
observations in galaxy surveys at different redshifts. We discuss the caveats
and interpretations of our results, and speculate that the strong structural
evolution found in some previous studies for early-type galaxies could be
explained partially by photometric changes rather than by intrinsic structural
changes.
