Chemical evolution of classical and ultra-faint dwarf spheroidal galaxies

Vincenzo, Fiorenzo; Matteucci, Francesca; Vattakunnel, Shaji; A. Lanfranchi, Gustavo

Abstract

We present updated chemical evolution models of two dwarf spheroidal galaxies (Sculptor and Carina) and the first detailed chemical evolution models of two ultra-faint dwarfs (Hercules and Bo\"otes I). Our results suggest that the dwarf spheroidals evolve with a low efficiency of star formation, confirming previous results, and the ultra-faint dwarfs with an even lower one. Under these assumptions, we can reproduce the stellar metallicity distribution function, the $[\alpha/Fe]$ vs. $[Fe/H]$ abundance patterns and the total stellar and gas masses observed at the present time in these objects. In particular, for the ultra-faint dwarfs we assume a strong initial burst of star formation, with the mass of the system being already in place at early times. On the other hand, for the classical dwarf spheroidals the agreement with the data is found by assuming the star formation histories suggested by the Color-Magnitude diagrams and a longer time-scale of formation via gas infall. We find that all these galaxies should experience galactic winds, starting in all cases before $1$ Gyr from the beginning of their evolution. From comparison with Galaxy data, we conclude that it is unlikely that the ultra-faint dwarfs have been the building blocks of the whole Galactic halo, although more data are necessary before drawing firm conclusions.

Citation

Vincenzo, F., Matteucci, F., Vattakunnel, S., & A. Lanfranchi, G. (2014). Chemical evolution of classical and ultra-faint dwarf spheroidal galaxies. Monthly notices of the Royal Astronomical Society, 441(4), 2815–2830. https://doi.org/10.1093/mnras/stu710

• Journal Article Type: Article
• Acceptance Date: Apr 8, 2014
• Online Publication Date: May 24, 2014
• Publication Date: Jul 11, 2014
• Deposit Date: Mar 12, 2022
• Publicly Available Date: Mar 28, 2022
• Journal: Monthly notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Publisher: Oxford University Press
• Peer Reviewed: Peer Reviewed
• Volume: 441
• Issue: 4
• Pages: 2815–2830
• DOI: https://doi.org/10.1093/mnras/stu710
• Keywords: Astrophysics of Galaxies
• Public URL: https://hull-repository.worktribe.com/output/3946314