Tests of model predictions for the responses of stellar spectra and absorption-line indices to element abundance variations

Autor(es)

Sansom, A. E. ^[1] ; de Castro Milone, A. ^[2] ; Vazdekis, A. ^{[3, 4]} ; Sanchez-Blazquez, P. ^[5]

Afiliação do(s) autor(es)

^[1] Univ Cent Lancashire, Sch Comp Engn & Phys Sci, Jeremiah Horrocks Inst, Preston PR1 2HE, Lancs - England

^[2] Inst Nacl Pesquisas Espaciais, Div Astrofis, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[3] Univ La Laguna, Dept Astrofis, E-38205 Tenerife - Spain

^[4] Inst Astrofis Canarias, E-38200 Tenerife - Spain

^[5] Univ Autonoma Madrid, Dept Fis Teor, E-28049 Madrid - Spain

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 435, n. 2, p. 952-974, OCT 2013.
• Citações Web of Science: 15

Resumo

A method that is widely used to analyse stellar populations in galaxies is to apply the theoretically derived responses of stellar spectra and line indices to element abundance variations, which are hereafter referred to as response functions. These are applied in a differential way, to base models, in order to generate spectra or indices with different abundance patterns. In this paper, sets of such response functions for three different stellar evolutionary stages are tested with new empirical {[}Mg/Fe] abundance data for the medium-resolution Isaac Newton Telescope library of empirical spectra (MILES). Recent theoretical models and observations are used to investigate the effects of {[}Fe/H], {[}Mg/H] and overall {[}Z/H] on spectra, via ratios of spectra for similar stars. The global effects of changes in abundance patterns are investigated empirically through direct comparisons of similar stars from MILES, highlighting the impact of abundance effects in the blue part of the spectrum, particularly for lower temperature stars. It is found that the relative behaviour of iron-sensitive line indices are generally well predicted by response functions, whereas Balmer line indices are not. Other indices tend to show large scatter about the predicted mean relations. Implications for element abundance and age studies in stellar populations are discussed and ways forward are suggested to improve the match with the behaviour of spectra and line-strength indices observed in real stars. (AU)

• Processo FAPESP: 12/04953-0 - Comparação dos dados empíricos da base espectral MILES contra modelos teóricos estelares para modelagem de populações estelares com enriquecimento alfa variável
• Beneficiário: Andre de Castro Milone
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional