Oral Presentation

Exploring the chemical evolution of dwarf galaxies in the Local Group

Author(s): Sena A. MATSUI(1), Tsutomu T. TAKEUCHI(1,2), Suchetha COORAY(1), Kiyoaki Christopher OMORI(1), Kai T. KONO (1) ((1)Nagoya University, (2)Institute of Statistical Mathematics)

Presenter: Sena Matsui (Nagoya University)

There are extremely faint and low-mass galaxies in the Universe, which are called dwarf spheroidal galaxies (dSphs). Generally dSphs do not have much interstellar medium, and are thought to have blown it away by galactic scale winds. Therefore, they have little star formation activity and are dark-matter dominated. The purpose of this study is to explore the history of star formation and chemical evolution of dwarf galaxies by examining the relationship between mass and metallicity in these dSph and other Local Group dwarf galaxies.
For dSphs, [Fe/H] is almost the only metallicity indicator, and we adopted it in this study. [Fe/H] is a measure of the metallicity of stellar populations, and its dependence on the star formation history is generally different from that of 12 + log(O/H), which is a measure of the metallicity of the ISM.
In this study, we calculated the virial mass and stellar mass, and explored their relationship to luminosity and metallicity. The main result is that the stellar mass-metallicity relation shows a similar correlation to larger galaxies than to dwarf galaxies. In addition, we found a negative correlation between the virial mass-luminosity relation. We will describe these details and other results. We will also compare the tidal effects and the onset timescale of the galactic wind.