The Elemental Abundance Distributions of Milky Way Satellite Galaxies

Дата и время публикации : 2010-11-06T01:01:32Z

Авторы публикации и институты :
Evan N. Kirby (California Institute of Technology)

Ссылка на журнал-издание: 2011 EAS Pub. Ser., 48, 19
Коментарии к cтатье: 6 pages, 4 figures, proceeding of oral contribution to A Universe of Dwarf Galaxies, Lyon, France, July 2010
Первичная категория: astro-ph.GA

Все категории : astro-ph.GA

Краткий обзор статьи: The chemical compositions of the stars in Milky Way (MW) satellite galaxies reveals the history of gas flows and star formation (SF) intensity. This talk presented a Keck/DEIMOS spectroscopic survey of the Fe, Mg, Si, Ca, and Ti abundances of nearly 3000 red giants in eight MW dwarf satellites. The metallicity and alpha-to-iron ratio distributions obey the following trends: (1) The more luminous galaxies are more metal-rich, indicating that they retained gas more efficiently than the less luminous galaxies. (2) The shapes of the metallicity distributions of the more luminous galaxies require gas infall during their SF lifetimes. (3) At [Fe/H] < -1.5, [alpha/Fe] falls monotonically with increasing [Fe/H] in all MW satellites. One interpretation of these trends is that the SF timescale in any MW satellite is long enough that Type Ia supernovae exploded for nearly the entire SF lifetime.

Category: Physics