The chemical evolution of galaxies with a variable integrated galactic initial mass function

摘要: ABSTRACT Standard analytical chemical evolution modelling of galaxies has been assuming thestellar initial mass function (IMF) to be invariant and fully sampled allowing fractionsof massive stars contribute even in dwarf with very low star formationrates (SFRs). Recent observations show the integrated galactic function(IGIMF) stars, i.e. galaxy-wide IMF, become systematically top-heavy withincreasing SFR. This predicted by IGIMF theory, which is here usedto develop theory galaxies. theoryis non-linear requires iterative solution implicit integral equations due tothe dependence on metallicity It shown thatthe mass–metallicity relation emerges naturally, although at masses thetheoreticalpredictionsoverestimatethe observationsby 0.3–0.4dex. A good agreementwith observation can obtained only if gas flows are taken into account. Inparticular, we able reproduce observed Lee etal. (2006) modest amounts infall an outflow rate decreasesas a mass. The rates required fit data areconsiderably smaller than models IMFs.Key words: Stars: abundances – stars: luminosity function, su-pernovae: general Galaxies: clusters:general