NOAO >   Observing Info >   Approved Programs >   2011B-0332

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Proposal Information for 2011B-0332


PI: Andrea Kunder, Cerro Tololo Inter-American Observatory, akunder@ctio.noao.edu
Address: Casilla 603, La Serena, Chile

CoI: Roberto De Propris, Cerro Tololo Inter-American Observatory
CoI: R. Mike Rich, UCLA

Title: Structure of the Galactic Bulge from Infrared Photometry of RR Lyrae Variables

Abstract: Bulge RR Lyrae variables are standard candles which can be used to obtain a distance to the Galactic center with only a few percent uncertainty. Bulge RR Lyrae are also thought to be the oldest stellar population of our Galaxy. Unfortunately, there is very little precision photometry in the literature with which to map out the Galactic Bulge and constrain theories of the formation of the Milky Way. We ask for 8 nights (16\times0.5 nights) at the Blanco telescope with NEWFIRM in order to obtain precision photometry of ~250 known RR Lyrae in the near-IR, and do a new deep search for RR Lyrae in Baade's window and Betty Blanco's Window (WI). There is evidence that previous searches of RR Lyrae in the bulge are incomplete, even in Baade's window, the best studied bulge field. In combination with the optical microlensing searches, we should obtain a complete sample of RR Lyrae in these low extinction windows. The resulting analysis will allow the oldest part of the bar to be traced out as a function of Galactic longitude, place age constraints for the complex structure of the double red clump, and normalize the RR Lyrae density distribution, and to match it with the well known distribution of halo RR Lyrae.


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