To use or not to use synthetic stellar spectra in population synthesis models?

Autor(es)

Coelho, Paula R. T. ^[1] ; Bruzual, Gustavo ^[2] ; Charlot, Stephane ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Rua Matao 1226, BR-05508090 Sao Paulo - Brazil

^[2] UNAM, Inst Radioastron & Astrofis, Campus Morelia, Morelia 58089, Michoacan - Mexico

^[3] Sorbonne Univ, CNRS, UMR7095, Inst Astrophys Paris, F-75014 Paris - France

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 491, n. 2, p. 2025-2042, JAN 2020.
• Citações Web of Science: 0

Resumo

Stellar population synthesis (SPS) models are invaluable to study star clusters and galaxies. They provide means to extract stellar masses, stellar ages, star formation histories, chemical enrichment, and dust content of galaxies from their integrated spectral energy distributions, colours, or spectra. As most models, they contain uncertainties that can hamper our ability to model and interpret observed spectra. This work aims at studying a specific source of model uncertainty: the choice of an empirical versus a synthetic stellar spectral library. Empirical libraries suffer from limited coverage of parameter space, while synthetic libraries suffer from modelling inaccuracies. Given our current inability to have both ideal stellar-parameter coverage with ideal stellar spectra, what should one favour: better coverage of the parameters (synthetic library) or better spectra on a star-by-star basis (empirical library)? To study this question, we build a synthetic stellar library mimicking the coverage of an empirical library, and SPS models with different choices of stellar library tailored to these investigations. Through the comparison of model predictions and the spectral fitting of a sample of nearby galaxies, we learned that predicted colours are more affected by the coverage effect than the choice of a synthetic versus empirical library; the effects on predicted spectral indices are multiple and defy simple conclusions; derived galaxy ages are virtually unaffected by the choice of the library, but are underestimated when SPS models with limited parameter coverage are used; metallicities are robust against limited HRD coverage, but are underestimated when using synthetic libraries. (AU)

• Processo FAPESP: 18/05392-8 - Uma nova biblioteca de modelos de população estelar puramente teóricos
• Beneficiário: Paula Rodrigues Teixeira Coelho
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 17/02375-2 - Modelos de população estelar teóricos vs. semi-empíricos: um experimento controlado
• Beneficiário: Paula Rodrigues Teixeira Coelho
• Modalidade de apoio: Auxílio à Pesquisa - Pesquisador Visitante - Internacional