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Connection between dynamically derived IMF normalisation and stellar populations

Published online by Cambridge University Press:  10 April 2015

Richard M. McDermid*
Affiliation:
Department of Physics and Astronomy, Macquarie University, Sydney NSW 2109, Australia Australian Astronomical Observatory, PO Box 915, Sydney NSW 1670, Australia email: richard.mcdermid@mq.edu.au
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Abstract

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In this contributed talk I present recent results on the connection between stellar population properties and the normalisation of the stellar initial mass function (IMF) measured using stellar dynamics, based on a large sample of 260 early-type galaxies observed as part of the ATLAS3D project. This measure of the IMF normalisation is found to vary non-uniformly with age- and metallicity-sensitive absorption line strengths. Applying single stellar population models, there are weak but measurable trends of the IMF with age and abundance ratio. Accounting for the dependence of stellar population parameters on velocity dispersion effectively removes these trends, but subsequently introduces a trend with metallicity, such that ‘heavy’ IMFs favour lower metallicities. The correlations are weaker than those found from previous studies directly detecting low-mass stars, suggesting some degree of tension between the different approaches of measuring the IMF. Resolving these discrepancies will be the focus of future work.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2015 

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