AAS 203rd Meeting, January 2004
Session 112 The Milky Way and Its Environs
Poster, Thursday, January 8, 2004, 9:20am-4:00pm, Grand Hall

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[112.14] The Yale/San Juan Proper Motion Program: A 2003 Status Report

T. M. Girard, D. I. Dinescu, W. F. van Altena, V. I. Korchagin (Yale Univ.), T. C. Beers (Michigan State Univ.), I. Platais (Johns Hopkins Univ.), C. E. Lopez (Univ. de San Juan, Argentina), D. G. Monet (USNO-Flagstaff)

The current status of the Yale/San Juan SPM program is presented. The recently released SPM3 Catalog is a near-complete catalog to V=17.5, providing absolute proper motions for 10.7 million objects. The proper-motion precision, for well-measured stars, is 4 mas/yr and the estimated systematic uncertainty is 0.4 mas/yr. In addition to our photographic B and V magnitudes, a cross-identification with the 2MASS all sky survey provides high-quality infrared photometry for virtually all SPM3 objects. As an example of the Catalog's scientific value, we present two simple applications of the SPM3 data: 1) a measure of the velocity shear, as a function of z, at the South Galactic Pole, and 2) a kinematic classification of Rodgers' metal-poor, main-sequence A stars.

The second-epoch of the SPM is currently being completed with CCD observations, using the same 51-cm double astrograph at El Leoncito, Argentina that was employed in the first-epoch photography. The camera system is described and, as a test case, the CCD data are used to measure the absolute proper motion of the bulge globular cluster, NGC5927.

The primary motivation of the SPM program is to provide fundamental data for kinematic studies of the various components of the Milky Way. Recent objective-prism surveys in the southern hemisphere have produced thousands of radial velocities and metallicity estimates for stars of the thick-disk and halo populations. In the near future, the RAVE-II survey will obtain similar information for tens of millions of stars. When combined with accurate proper motions from SPM, we will have the opportunity for unprecedented analysis of the kinematic and dynamical properties of the thick-disk and halo populations.

This work has received partial support from NSF grants AST-0098508, AST-0098549, AST-0098548, and AST-0098687.

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