Bibcode
Weidner, C.; Ferreras, Ignacio; Vazdekis, A.; La Barbera, Francesco
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 435, Issue 3, p.2274-2280
Advertised on:
11
2013
Citations
79
Refereed citations
72
Description
Recent evidence based independently on spectral line strengths and
dynamical modelling point towards a non-universal stellar initial mass
function (IMF), probably implying an excess of low-mass stars in
elliptical galaxies with a high velocity dispersion. 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
starbursting 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, α-enhancement,
mass-to-light ratio or the mass fraction of the stellar component in
low-mass stars.
Related projects
Traces of Galaxy Formation: Stellar populations, Dynamics and Morphology
We are a large, diverse, and very active research group aiming to provide a comprehensive picture for the formation of galaxies in the Universe. Rooted in detailed stellar population analysis, we are constantly exploring and developing new tools and ideas to understand how galaxies came to be what we now observe.
Ignacio
Martín Navarro