NOAO >   Observing Info >   Approved Programs >   2007B-0305

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Proposal Information for 2007B-0305


PI: Lissa Miller, Yale University, lissa.miller@yale.edu
Address: Astronomy Department, P.O. Box 208101, New Haven, CT 06520-8101, USA

CoI: Andrew Szymkowiak, Yale University
CoI: Robert Zinn, Yale University
CoI: Sonia Duffau, Universidad de Chile
CoI: A. Katherina Vivas, CIDA, Venezuela

Title: Spectroscopy of RR Lyrae Variables in Halo Substructures

Abstract: Spectroscopic observations with the 2.1m telescope and the WHTSS are proposed of RR Lyrae variables (RRL) identified by QUEST and Palomar- QUEST sky surveys. The majority of the targets are in regions of high RRL densities that may be halo substructures. The radial velocities of these stars will test if the stars are moving on similar orbits. These measurements should also show if the RRLs that are not members of halo substructures have the mean retrograde rotation about the galactic center and a high velocity dispersion, similar to what Kinman et al. (2007) have found for a more nearby sample of RRLs. The identification of Halo substructures and the possible retrograde rotation of the field RRLs have an impact on the hierarchical picture of galaxy formation, which predicts that Galactic halo is made up of the debris from the mergers of many small galaxies with the Milky Way. These observations will be part of the Ph.D. thesis of Lissa Miller. An additional goal is to continue the science verification of the WHTSS.


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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