CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS

We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the ATLAS(3D) project. We study trends between our dynamically derived IMF normalization alpha(dyn) equivalent to (M/L)(stars)/(M/L)(Salp) and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [alpha/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalization of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of alpha(dyn) at a given population parameter. As a result, we find weak alpha(dyn)-[alpha/Fe] and alpha(dyn)-Age correlations and no significant alpha(dyn)-[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalization via the low-mass star demographics inferred through stellar spectral analysis.