Connection between dynamically derived initial mass function normalisation and stellar population parameters

Richard M. McDermid, Michele Cappellari, Katherine Alatalo, Estelle Bayet, Leo Blitz, Maxime Bois, Frederic Bournaud, Martin Bureau, Alison F. Crocker, Roger L. Davies, Timothy A. Davis, P. T. de Zeeuw, Pierre-Alain Duc, Eric Emsellem, Sadegh Khochfar, Davor Krajnovic, Harald Kuntschner, Raffaella Morganti, Thorsten Naab, Tom OosterlooMarc Sarzi, Nicholas Scott, Paolo Serra, Anne-Marie Weijmans, Lisa M. Young

Research output: Contribution to journalArticlepeer-review

42 Citations (Scopus)


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.

Original languageEnglish
Article numberL37
Number of pages5
JournalAstrophysical Journal Letters
Issue number2
Publication statusPublished - 27 Aug 2014


  • Galaxies: abundances
  • Galaxies: elliptical and lenticular, cD
  • Galaxies: kinematics and dynamics
  • Galaxies: stellar content


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