The High Redshift Universe Next Door (Speaker: Joshua Simon)

Tuesday December 10, 2013 4:00 pm

Abstract: The dwarf galaxies around the Milky Way are extremely valuable laboratories for studying the nature of dark matter, the threshold for galaxy formation, and chemical evolution in the early universe. After reviewing the revolution in our understanding of the Milky Way’s satellite population that resulted from the Sloan Digital Sky Survey, I will discuss how these objects provide unique new windows into processes that occurred at high redshift and can usually only be studied in the distant universe. Spectroscopy at both low and high resolution shows that a significant fraction of the stars in the least luminous galaxies are extremely metal-poor, with [Fe/H] less than -3. I will describe a new survey using the Magellan telescopes that aims to identify a complete sample of the most metal-poor stars in Milky Way dwarfs. The chemical abundance patterns of extremely metal-poor stars are nearly identical in all galaxies where they are currently known, despite their host galaxies spanning a factor of 10^8 in luminosity, which suggests that the initial chemical evolution of all galaxies may be universal. These extremely metal-poor stars also have abundances that are consistent with model predictions for Population III nucleosynthesis, offering the possibility of constraining the first generation of stars that formed in our nearest galactic neighbors.

Event Contact

Debbie Meinbresse