Weidner, Carsten
Bibliographical reference
PROBING STELLAR POPULATIONS OUT TO THE DISTANT UNIVERSE: CEFALU 2008, Proceedings of the International Conference. AIP Conference Proceedings, Volume 1111, pp. 129-136 (2009).
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5
2009
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Description
Over the past years observations of young and populous star clusters
have shown that the stellar IMF appears to be an invariant featureless
Salpeter power-law with an exponent α = 2.35 for stars more
massive than a few Msolar. A consensus has also emerged that
most, if not all, stars form in stellar groups and star clusters, and
that the mass function of young star clusters in the solar-neighbourhood
and in interacting galaxies can be described, over the mass range of a
few 10Msolar to 107Msolar, as a
power-law with an exponent β~2. Under the assumption of a relation
between the most-massive star in a cluster and the cluster mass these
two results imply that integrated galactic-field IMFs for early-type
stars cannot be a Salpeter power-law, but that they must have a steeper
exponent [1]. Furthermore, the empirical correlation between galactic
star-formation rate (SFR) and the mass of the most massive cluster that
forms in a galaxy [2] implies that dwarf galaxies that have low average
star-formation rates will have substantially different integrated IMFs
than massive galaxies such as our Milky Way [3]. This has important
consequences for the distribution of stellar remnants and for the
chemo-dynamical and photometric evolution of galaxies. These results
suggest that dwarf galaxies ought to show large variations in their
integrated field-star IMFs and consequently in their chemical
enrichment, while massive galaxies tend to have the same integrated
field IMFs with a corresponding smaller inter-galactic scatter in
chemical abundances.