University of Hertfordshire

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Modern yields per stellar generation: the effect of the IMF

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  • stv2598

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  • Fiorenzo Vincenzo
  • Francesca Matteucci
  • Francesco Belfiore
  • Roberto Maiolino
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Original languageEnglish
Article numberstv2598
Pages (from-to)4183-4190
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Early online date4 Dec 2015
Publication statusPublished - 1 Feb 2016


Gaseous and stellar metallicities in galaxies are nowadays routinely used to constrain the evolutionary processes in galaxies. This requires the knowledge of the average yield per stellar generation, yZ, i.e. the quantity of metals that a stellar population releases into the interstellar medium (ISM), which is generally assumed to be a fixed fiducial value. Deviations of the observed metallicity from the expected value of yZ are used to quantify the effect of outflows or inflows of gas, or even as evidence for biased metallicity calibrations or inaccurate metallicity diagnostics. Here, we show that yZ depends significantly on the initial mass function (IMF), varying by up to a factor larger than three, for the range of IMFs typically adopted in various studies. Varying the upper mass cutoff of the IMF implies a further variation of yZ by an additional factor that can be larger than two. These effects, along with the variation of the gas mass fraction restored into the ISM by supernovae (R, which also depends on the IMF), may yield to deceiving results, if not properly taken into account. In particular, metallicities that are often considered unusually high can actually be explained in terms of yield associated with commonly adopted IMFs such as the Kroupa or Chabrier. We provide our results for two different sets of stellar yields (both affected by specific limitations) finding that the uncertainty introduced by this assumption can be as large as ∼0.2 dex. Finally, we show that yZ is not substantially affected by the initial stellar metallicity as long as Z > 10−3 Z.


This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2015 The Author (s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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