Kinetys II: Constraints on spatial variations of the stellar initial
  mass function from K-band spectroscopy
  We investigate the spatially resolved stellar populations of a sample of
seven nearby massive Early-type galaxies (ETGs), using optical and near
infrared data, including K-band spectroscopy. This data offers good prospects
for mitigating the uncertainties inherent in stellar population modelling by
making a wide variety of strong spectroscopic features available. We report new
VLT-KMOS measurements of the average empirical radial gradients out to the
effective radius in the strengths of the Ca I 1.98$\mu$m and 2.26$\mu$m
features, the Na I 2.21$\mu$m line, and the CO 2.30$\mu$m bandhead. Following
previous work, which has indicated an excess of dwarf stars in the cores of
massive ETGs, we pay specific attention to radial variations in the stellar
initial mass function (IMF) as well as modelling the chemical abundance
patterns and stellar population ages in our sample. Using state-of-the-art
stellar population models we infer an [Fe/H] gradient of -0.16$\pm$0.05 per dex
in fractional radius and an average [Na/Fe] gradient of -0.35$\pm$0.09. We find
a large but radially-constant enhancement to [Mg/Fe] of $\sim$ 0.4 and a much
lower [Ca/Fe] enhancement of $\sim$ 0.1. Finally, we find no significant IMF
radial gradient in our sample on average and find that most galaxies in our
sample are consistent with having a Milky Way-like IMF, or at most a modestly
bottom heavy IMF (e.g. less dwarf enriched than a single power law IMF with the
Salpeter slope).
