| Full text | |
| Author(s): |
Vazdekis, A.
[1, 2]
;
Coelho, P.
[3]
;
Cassisi, S.
[4]
;
Ricciardelli, E.
[5]
;
Falcon-Barroso, J.
[1, 2]
;
Sanchez-Blazquez, P.
[6]
;
La Barbera, F.
[7]
;
Beasley, M. A.
[1, 2]
;
Pietrinferni, A.
[4]
Total Authors: 9
|
| Affiliation: | [1] IAC, E-38200 San Cristobal la Laguna, Tenerife - Spain
[2] Univ La Laguna, Dept Astrofis, E-38205 Tenerife - Spain
[3] Univ Fed Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo - Brazil
[4] INAF Osservatorio Astron Collurania, I-64100 Teramo - Italy
[5] Univ Valencia, Dept Astron & Astrofis, E-46100 Valencia - Spain
[6] Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid - Spain
[7] INAF Osservatorio Astron Capodimonte, I-80131 Naples - Italy
Total Affiliations: 7
|
| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 449, n. 2, p. 1177-1214, MAY 11 2015. |
| Web of Science Citations: | 91 |
| Abstract | |
We present models that predict spectra of old-and intermediate-aged stellar populations at 2.51 angstrom (FWHM) with varying {[}alpha/Fe] abundance. The models are based on the MILES library and on corrections from theoretical stellar spectra. The models employ recent {[}Mg/Fe] determinations for the MILES stars and BaSTI scaled-solar and alpha-enhanced isochrones. We compute models for a suite of initial mass function (IMF) shapes and slopes, covering a wide age/metallicity range. Using BaSTI, we also compute `base models' matching the Galactic abundance pattern. We confirm that the alpha-enhanced models show a flux excess with respect to the scaled-solar models blueward similar to 4500 angstrom, which increases with age and metallicity. We also confirm that both {[}MgFe] and {[}MgFe]' indices are {[}alpha/Fe]-insensitive. We show that the sensitivity of the higher order Balmer lines to {[}alpha/Fe] resides in their pseudo-continua, with narrower index definitions yielding lower sensitivity. We confirm that the alpha-enhanced models yield bluer (redder) colours in the blue (red) spectral range. To match optical colours of massive galaxies, we require both alpha-enhancement and a bottom-heavy IMF. The comparison of globular cluster line-strengths with our predictions match the {[}Mg/Fe] determinations from their individual stars. We obtain good fits to both full spectra and indices of galaxies with varying {[}alpha/Fe]. Using thousands of SDSS galaxy spectra, we obtain a linear relation between a proxy for the abundance, {[}Z(Mg)/Z(Fe)](SS(BaSTI)), using solely scaled-solarmodels and the {[}Mg/Fe] derived with models with varying abundance ({[}Mg/Fe] = 0.59{[}Z(Mg)/Z(Fe)](SS(BaSTI))). Finally, we provide a user-friendly, web-based facility, which allows composite populations with varying IMF and {[}alpha/Fe]. (AU) | |
| FAPESP's process: | 08/58406-4 - The modeling of stellar populations and detailed abundance patterns |
| Grantee: | Paula Rodrigues Teixeira Coelho |
| Support Opportunities: | Research Grants - Young Investigators Grants |
| FAPESP's process: | 09/09465-0 - The modeling of stellar populations and detailed abundance pattern |
| Grantee: | Paula Rodrigues Teixeira Coelho |
| Support Opportunities: | Scholarships in Brazil - Young Researchers |