UV upturn versus UV weak galaxies: differences and similarities of their stellar populations unveiled by a de-biased sample

Autor(es)

Dantas, M. L. L. ^[1] ; Coelho, P. R. T. ^[1] ; Sanchez-Blazquez, P. ^{[2, 3]}

Afiliação do(s) autor(es)

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

^[2] Univ Complutense Madrid, Dept Fis Tierra & Astrofis, E-28040 Madrid - Spain

^[3] Univ Complutense Madrid, Fac CC Fis, IPARCOS, E-28040 Madrid - Spain

• Tipo de documento: Artigo Científico
• Fonte: Monthly Notices of the Royal Astronomical Society; v. 500, n. 2, p. 1870-1883, JAN 2021.
• Citações Web of Science: 1

Resumo

The ultraviolet (UV) upturn is characterized by an unexpected up-rise of the UV flux in quiescent galaxies between the Lyman limit and 2500 A. By making use of colour-colour diagrams, one can subdivide UV bright red-sequence galaxies in two groups: UV weak and upturn. With these two groups, we propose a comparison between their stellar population properties with the goal of establishing differences and similarities between them. We make use of propensity score matching to mitigate potential biases between the two samples, by selecting similar objects in terms of redshift and stellar mass. Also, we take advantage of spectral energy distribution (SED) fitting results from MAGPHYS made available by the GAMA collaboration. The analyses are made by comparing the distributions from the SED fitting directly, as well as investigating the differences in correlations between their parameters, and finally by using principal component analysis. We explore important differences and similarities between UV weak and upturn galaxies in terms of several parameters, such as: metallicity, age, specific star formation rate, time of last burst of star-formation, to mention a few. Notable differences are those concerning (g - r) colour, metallicity, and time since last burst of star-formation: UV upturn are redder in the optical, more metallic, and their last burst of star-formation happened earlier in time. These differences suggest that UV upturn systems have shorter star-formation histories (i.e. have been evolving more passively) when compared to UV weak galaxies. Consequently, these last seem to have a higher diversity of stellar populations. (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