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Clues on the history of early-type galaxies from SDSS spectra and GALEX photometry

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Werle, A. ; Fernandes, R. Cid ; Asari, N. Vale ; Coelho, P. R. T. ; Bruzual, G. ; Charlot, S. ; de Carvalho, R. R. ; Herpich, F. R. ; de Oliveira, C. Mendes ; Sodr, L. ; Ruschel-Dutra, D. ; de Amorim, A. ; Sampaio, V. M.
Número total de Autores: 13
Tipo de documento: Artigo Científico
Fonte: Monthly Notices of the Royal Astronomical Society; v. 497, n. 3, p. 13-pg., 2020-09-01.
Resumo

Stellar population studies of early-type galaxies (ETGs) based on their optical stellar continuum suggest that these are quiescent systems. However, emission lines and ultraviolet photometry reveal a diverse population. We use a new version of the STARLIGHT spectral synthesis code and state-of-the-art stellar population models to simultaneously fit Sloan Digital Sky Survey spectra and Galaxy Evolution Explorer photometry for a sample of 3453 galaxies at z < 0.1 with near ultraviolet (NUV) - r > 5 that are classified as elliptical by Galaxy Zoo. We reproduce far ultraviolet (FUV) magnitudes for 80 per cent of UV upturn galaxies selected using criteria from the literature, suggesting that additional stellar population ingredients such as binaries and extreme horizontal branch stars may have a limited contribution to the UV upturn. The addition of ultraviolet data leads to a broadening of the distributions of mean stellar ages, metallicities, and attenuation. Stellar populations younger than 1 Gyr are required to reproduce the ultraviolet emission in 17 per cent of our sample. These systems represent 43 per cent of the sample at 5 < NUV - r < 5.5 and span the same stellar mass range as other ETGs in our sample. ETGs with young stellar components have larger H-alpha equivalent widths (W-H alpha) and larger dust attenuation. Emission line ratios and W-H alpha indicate that the ionizing source in these systems is a mixture of young and old stellar populations. Their young stellar populations are metal-poor, especially for high-mass galaxies, indicating recent star formation associated with rejuvenation events triggered by external processes, such as minor mergers. (AU)

Processo FAPESP: 19/01768-6 - Estrutura em larga escala no universo local com o levantamento de dados S-PLUS
Beneficiário:Ariel Werle
Modalidade de apoio: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico
Processo FAPESP: 12/00800-4 - O universo em 3-D: astrofísica com grandes levantamentos de galáxias
Beneficiário:Laerte Sodré Junior
Modalidade de apoio: Auxílio à Pesquisa - Temático
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: 19/11910-4 - Explorando dados do SAM-FP e T80-Sul
Beneficiário:Claudia Lucia Mendes de Oliveira
Modalidade de apoio: Auxílio à Pesquisa - Regular