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Paper: The Role of the Integrated Galactic Initial Mass Function in the Chemical Evolution of the Solar Neighborhood
Volume: 440, UP2010: Have Observations Revealed a Variable Upper End of the Initial Mass Function?
Page: 279
Authors: Calura, F.; Recchi, S.; Matteucci, F.; Kroupa, P.
Abstract: The integrated galactic initial mass function (IGIMF) is computed from the combination of the stellar initial mass function (IMF) and the embedded cluster mass function, described by a power law with index β. The result of the combination is a time-varying IMF which depends on the star formation rate. We applied the IGIMF formalism to a chemical evolution model for the Solar neighborhood and compared the results obtained by assuming three possible values for β with the ones obtained by means of a standard, well-tested, constant IMF. In general, a lower absolute value of β implies a flatter IGIMF, hence a larger number of massive stars, higher Type Ia and II supernova rates, higher mass ejection rates and higher [α/Fe] values at a given metallicity. Our suggested fiducial value for β is 2, since with this value we can account for most of the local observables. We discuss our results in a broader perspective, with some implications regarding the possible universality of the IMF and the importance of the star formation threshold.
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