Connection between dynamically derived IMF normalisation and stellar population parameters
Abstract
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 Atlas3D project. We study trends between our dynamically-derived IMF normalisation and absorption line strengths, and interpret these via single stellar population- (SSP-) 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 normalisation of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of normalisation at a given population parameter. As a result, we find weak IMF-[alpha/Fe] and IMF-age correlations, and no significant IMF-[Z/H] correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalisation via low-mass star demographics inferred through stellar spectral analysis.
Cite
@article{arxiv.1408.3189,
title = {Connection between dynamically derived IMF normalisation and stellar population parameters},
author = {Richard M. McDermid and Michele Cappellari and Katherine Alatalo and Estelle Bayet and Leo Blitz and Maxime Bois and Frederic Bournaud and Martin Bureau and Alison F. Crocker and Roger L. Davies and Timothy A. Davis and P. T. de Zeeuw and Pierre-Alain Duc and Eric Emsellem and Sadegh Khochfar and Davor Krajnovic and Harald Kuntschner and Raffaella Morganti and Thorsten Naab and Tom Oosterloo and Marc Sarzi and Nicholas Scott and Paolo Serra and Anne-Marie Weijmans and Lisa M. Young},
journal= {arXiv preprint arXiv:1408.3189},
year = {2015}
}
Comments
5 pages, 3 figures, accepted for publication in ApJL