Schedule Oct 03, 2008
New Perspective on the Bulge from Observations of Microlensed Dwarf Stars
Jennifer Johnson (Ohio State)

Our picture of the Galactic bulge has been dominated by studies of red giants, because they are bright enough to be studied in detail. However, observations of Galactic bulge dwarfs have many advantages, including measuring metallicities of turnoff stars, which are necessary for accurate ages, and measuring abundance ratios of elements that are not possible in giants. We describe a program to obtain and analyze high-resolution spectra of dwarfs that have been magnified by factors of ~100 because of microlensing. Because microlensing events can occur throughout the bulge, we observe stars in regions of the bulge where red giants have not yet been studied. We discuss preliminary results regarding the metallicity distribution function and the age of the bulge. We present results for the chemical evolution of the bulge for several new elements, including C, N, K, Cu, Zn and Ba.

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