%0 Generic %1 weidner2013galaxywide %A Weidner, Carsten %A Ferreras, Ignacio %A Vazdekis, Alexandre %A La Barbera, Francesco %D 2013 %K elliptical galaxy imf variation %T The (galaxy-wide) IMF in giant elliptical galaxies: From top to bottom %U http://arxiv.org/abs/1306.6332 %X Recent evidence based independently on spectral line strengths and dynamical modelling point towards a non-universal stellar Initial Mass Function (IMF), implying an excess of low-mass stars in the most massive elliptical galaxies. Here we show that a time-independent bottom-heavy IMF is compatible neither with the observed metal-rich populations found in giant ellipticals nor with the number of stellar remnants observed within these systems. We suggest a two-stage formation scenario involving a time-dependent IMF to reconcile these observational constraints. In this model, an early strong star-bursting stage with a top-heavy IMF is followed by a more prolonged stage with a bottom-heavy IMF. Such model is physically motivated by the fact that a sustained high star formation will bring the interstellar medium to a state of pressure, temperature and turbulence that can drastically alter the fragmentation of the gaseous component into small clumps, promoting the formation of low-mass stars. This toy model is in good agreement with the different observational constrains on massive elliptical galaxies, such as age, metallicity, alpha-enhancement, M/L, or the mass fraction of the stellar component in low-mass stars.

@misc{weidner2013galaxywide, abstract = {Recent evidence based independently on spectral line strengths and dynamical modelling point towards a non-universal stellar Initial Mass Function (IMF), implying an excess of low-mass stars in the most massive elliptical galaxies. Here we show that a time-independent bottom-heavy IMF is compatible neither with the observed metal-rich populations found in giant ellipticals nor with the number of stellar remnants observed within these systems. We suggest a two-stage formation scenario involving a time-dependent IMF to reconcile these observational constraints. In this model, an early strong star-bursting stage with a top-heavy IMF is followed by a more prolonged stage with a bottom-heavy IMF. Such model is physically motivated by the fact that a sustained high star formation will bring the interstellar medium to a state of pressure, temperature and turbulence that can drastically alter the fragmentation of the gaseous component into small clumps, promoting the formation of low-mass stars. This toy model is in good agreement with the different observational constrains on massive elliptical galaxies, such as age, metallicity, alpha-enhancement, M/L, or the mass fraction of the stellar component in low-mass stars.}, added-at = {2013-06-28T08:21:30.000+0200}, author = {Weidner, Carsten and Ferreras, Ignacio and Vazdekis, Alexandre and La Barbera, Francesco}, biburl = {https://www.bibsonomy.org/bibtex/2afb7bfbc572ec724645c92668b66b4ff/miki}, description = {[1306.6332] The (galaxy-wide) IMF in giant elliptical galaxies: From top to bottom}, interhash = {8b8a502c7182eacff9c0144c7614f2f9}, intrahash = {afb7bfbc572ec724645c92668b66b4ff}, keywords = {elliptical galaxy imf variation}, note = {cite arxiv:1306.6332Comment: 5 pages, 3 figures, submitted to MNRAS}, timestamp = {2013-06-28T08:21:30.000+0200}, title = {The (galaxy-wide) IMF in giant elliptical galaxies: From top to bottom}, url = {http://arxiv.org/abs/1306.6332}, year = 2013 }