Stellar Population and Elemental Abundance Gradients of Early-type
  Galaxies
  The evolution of galaxies is imprinted in their stellar populations. Several
stellar population properties in massive early-type galaxies have been shown to
correlate with intrinsic galaxy properties like the galaxy's central velocity
dispersion, suggesting that stars formed in an initial collapse of gas (z~2).
However, stellar populations change as a function of galaxy radius, and it is
not clear how local gradients of individual galaxies are influenced by global
galaxy properties and galaxy environment. In this paper, we study the stellar
populations of eight early-type galaxies as a function of radius. We use
optical spectroscopy (~4000-8600 \r{A}) and full-spectral fitting to measure
stellar population age, metallicity, IMF slope, and nine elemental abundances
(O, Mg, Si, Ca, Ti, C, N, Na, Fe) out to 1 R_e for each galaxy individually. We
find a wide range of properties, with ages ranging from 3-13 Gyr. Some galaxies
have a radially constant, Salpeter-like IMF, and other galaxies have a
super-Salpeter IMF in the center, decreasing to a sub-Salpeter IMF at ~0.5 R_e.
We find a global correlation of the central [Z/H] to the central IMF and the
radial gradient of the IMF for the eight galaxies, but local correlations of
the IMF slope to other stellar population parameters hold only for subsets of
the galaxies in our sample. Some elemental abundances also correlate locally
with each other within a galaxy, suggesting a common production channel. Those
local correlations appear only in subsets of our galaxies indicating variations
of the stellar content among different galaxies.
