%0 Generic %1 fontanot2016variations %A Fontanot, Fabio %A De Lucia, Gabriella %A Hirschmann, Michaela %A Bruzual, Gustavo %A Charlot, Stephane %A Zibetti, Stefano %D 2016 %K function igimf initial mass variation %T Variations of the initial mass function in semi-analytical models: implications for the chemical enrichment of galaxies in the GAEA model %U http://arxiv.org/abs/1606.01908 %X In this work, we investigate the implications of the Integrated Galaxy-wide stellar Initial Mass Function (IGIMF) approach in the framework of the semi-analytic model GAEA (GAlaxy Evolution and Assembly), which features a detailed treatment of chemical enrichment and stellar feedback. The IGIMF provides an analytic description of the dependence of the stellar IMF shape on the rate of star formation in galaxies. We find that our model with a universal IMF predicts a rather flat $\alpha$/Fe-stellar mass relation. The model assuming the IGIMF, instead, is able to reproduce the observed increase of $\alpha$-enhancement with stellar mass. This is mainly due to the fact that massive galaxies are characterized by larger SFRs at high-redshift, leading to stronger $\alpha$-enhancement with respect to low-mass galaxies. At the same time, the IGIMF hypothesis does not affect significantly the trend for shorter star formation timescales for more massive galaxies. We argue that in the IGIMF scenario the $\alpha$/Fe ratios are good tracers of the highest SFR events, but they do not provide much information on the overall star formation timescales. The final stellar masses and mass-to-light-ratio of our model galaxies are larger than those estimated from the synthetic photometry assuming a universal IMF. This result is in agreement with recent claims of a bottom-heavier IMF in massive galaxies, based on dynamical analyses of local early type galaxies.

@misc{fontanot2016variations, abstract = {In this work, we investigate the implications of the Integrated Galaxy-wide stellar Initial Mass Function (IGIMF) approach in the framework of the semi-analytic model GAEA (GAlaxy Evolution and Assembly), which features a detailed treatment of chemical enrichment and stellar feedback. The IGIMF provides an analytic description of the dependence of the stellar IMF shape on the rate of star formation in galaxies. We find that our model with a universal IMF predicts a rather flat [$\alpha$/Fe]-stellar mass relation. The model assuming the IGIMF, instead, is able to reproduce the observed increase of $\alpha$-enhancement with stellar mass. This is mainly due to the fact that massive galaxies are characterized by larger SFRs at high-redshift, leading to stronger $\alpha$-enhancement with respect to low-mass galaxies. At the same time, the IGIMF hypothesis does not affect significantly the trend for shorter star formation timescales for more massive galaxies. We argue that in the IGIMF scenario the [$\alpha$/Fe] ratios are good tracers of the highest SFR events, but they do not provide much information on the overall star formation timescales. The final stellar masses and mass-to-light-ratio of our model galaxies are larger than those estimated from the synthetic photometry assuming a universal IMF. This result is in agreement with recent claims of a bottom-heavier IMF in massive galaxies, based on dynamical analyses of local early type galaxies.}, added-at = {2016-06-08T09:13:17.000+0200}, author = {Fontanot, Fabio and De Lucia, Gabriella and Hirschmann, Michaela and Bruzual, Gustavo and Charlot, Stephane and Zibetti, Stefano}, biburl = {https://www.bibsonomy.org/bibtex/2de931435abf0d705765f2f843f117b0e/miki}, description = {[1606.01908] Variations of the initial mass function in semi-analytical models: implications for the chemical enrichment of galaxies in the GAEA model}, interhash = {c805fa33ba0d6d8bd6ff3fd2d985b695}, intrahash = {de931435abf0d705765f2f843f117b0e}, keywords = {function igimf initial mass variation}, note = {cite arxiv:1606.01908Comment: 13 pages, 8 figures, 2 tables, submitted to MNRAS}, timestamp = {2016-06-08T09:13:17.000+0200}, title = {Variations of the initial mass function in semi-analytical models: implications for the chemical enrichment of galaxies in the GAEA model}, url = {http://arxiv.org/abs/1606.01908}, year = 2016 }