Edinburgh Research Explorer

Connection between Dynamically Derived Initial Mass Function Normalization and Stellar Population Parameters

Research output: Contribution to journalArticle

  • Richard M. McDermid
  • Michele Cappellari
  • Katherine Alatalo
  • Estelle Bayet
  • Leo Blitz
  • Maxime Bois
  • Frédéric Bournaud
  • Martin Bureau
  • Alison F. Crocker
  • Roger L. Davies
  • Timothy A. Davis
  • P. T. De Zeeuw
  • Pierre Alain Duc
  • Eric Emsellem
  • Davor Krajnović
  • Harald Kuntschner
  • Raffaella Morganti
  • Thorsten Naab
  • Tom Oosterloo
  • Marc Sarzi
  • Nicholas Scott
  • Paolo Serra
  • Anne Marie Weijmans
  • Lisa M. Young

Related Edinburgh Organisations

Original languageEnglish
Article numberL37
JournalAstrophysical Journal Letters
Issue number2
Publication statusPublished - 10 Sep 2014


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 normalization αdyn ≡ (M/L)stars/(M/L)Salp and absorption line strengths, and interpret these via single stellar population-equivalent ages, abundance ratios (measured as [α/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 αdyn at a given population parameter. As a result, we find weak αdyn-[α/Fe] and αdyn -Age correlations and no significant αdyn -[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.

    Research areas

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

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