Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF
We make use of a semi-analytical model of galaxy formation to investigate the origin of the observed correlation between [α/Fe] abundance ratios and stellar mass in elliptical galaxies.We implement a new galaxy-wide stellar initial mass function (IMF; top-heavy integrated galaxy initial mass functio...
Guardado en:
| Autores principales: | , , , , , , , , |
|---|---|
| Formato: | Articulo |
| Lenguaje: | Inglés |
| Publicado: |
2014
|
| Materias: | |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/85328 |
| Aporte de: |
| id |
I19-R120-10915-85328 |
|---|---|
| record_format |
dspace |
| institution |
Universidad Nacional de La Plata |
| institution_str |
I-19 |
| repository_str |
R-120 |
| collection |
SEDICI (UNLP) |
| language |
Inglés |
| topic |
Ciencias Astronómicas Galaxies: abundances Galaxies: formation Methods: numerical |
| spellingShingle |
Ciencias Astronómicas Galaxies: abundances Galaxies: formation Methods: numerical Gargiulo, Ignacio Daniel Cora, Sofía Alejandra Padilla, N.D. Muñoz Arancibia, A.M. Ruiz, A.N. Orsi, A.A. Tecce, T.E. Weidner, C. Bruzual, G. Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| topic_facet |
Ciencias Astronómicas Galaxies: abundances Galaxies: formation Methods: numerical |
| description |
We make use of a semi-analytical model of galaxy formation to investigate the origin of the observed correlation between [α/Fe] abundance ratios and stellar mass in elliptical galaxies.We implement a new galaxy-wide stellar initial mass function (IMF; top-heavy integrated galaxy initial mass function, TH-IGIMF) in the semi-analytic model SAG (acronym for semi-analytic galaxies) and evaluate its impact on the chemical evolution of galaxies. The star formation rate (SFR) dependence of the slope of the TH-IGIMF is found to be key to reproducing the correct [α/Fe]-stellar mass relation. Massive galaxies reach higher [α/Fe] abundance ratios because they are characterized by more top-heavy IMFs as a result of their higher SFR. As a consequence of our analysis, the value of the minimum embedded star cluster mass and of the slope of the embedded cluster mass function, which are free parameters involved in the TH-IGIMF theory, are found to be as lowas 5 and 2M⊙, respectively. Amild downsizing trend is present for galaxies generated assuming either a universal IMF or a variable TH-IGIMF.We find that, regardless of galaxy mass, older galaxies (with formation redshifts ≳2) are formed in shorter time-scales (≲2 Gyr), thus achieving larger [α/Fe] values. Hence, the time-scale of galaxy formation alone cannot explain the slope of the [α/Fe]-galaxy mass relation, but is responsible for the big dispersion of [α/Fe] abundance ratios at fixed stellar mass. We further test the hypothesis of a TH-IGIMF in elliptical galaxies by looking into mass-to-light ratios, and luminosity functions. Models with a TH-IGIMF are also favoured by these constraints. In particular, mass-to-light ratios agree with observed values for massive galaxies while being overpredicted for less massive ones; this overprediction is present regardless of the IMF considered. |
| format |
Articulo Articulo |
| author |
Gargiulo, Ignacio Daniel Cora, Sofía Alejandra Padilla, N.D. Muñoz Arancibia, A.M. Ruiz, A.N. Orsi, A.A. Tecce, T.E. Weidner, C. Bruzual, G. |
| author_facet |
Gargiulo, Ignacio Daniel Cora, Sofía Alejandra Padilla, N.D. Muñoz Arancibia, A.M. Ruiz, A.N. Orsi, A.A. Tecce, T.E. Weidner, C. Bruzual, G. |
| author_sort |
Gargiulo, Ignacio Daniel |
| title |
Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| title_short |
Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| title_full |
Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| title_fullStr |
Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| title_full_unstemmed |
Chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy IGIMF |
| title_sort |
chemoarchaeological downsizing in a hierarchical universe: impact of a top-heavy igimf |
| publishDate |
2014 |
| url |
http://sedici.unlp.edu.ar/handle/10915/85328 |
| work_keys_str_mv |
AT gargiuloignaciodaniel chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT corasofiaalejandra chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT padilland chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT munozarancibiaam chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT ruizan chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT orsiaa chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT teccete chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT weidnerc chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf AT bruzualg chemoarchaeologicaldownsizinginahierarchicaluniverseimpactofatopheavyigimf |
| bdutipo_str |
Repositorios |
| _version_ |
1764820489277014018 |