The funds from this RAPID proposal are used to replace a broken cooling system for the primary 4Kx4K PixelVision CCD camera on the Yale Southern Observatory (YSO) 51-cm double astrograph located at Cesco Observatory in El Leoncito, Argentina. The Cesco Observatory is operated jointly by the Yale Southern Observatory and the Universidad Nacional de San Juan (UNSJ).
The cooling system is essential for operating the primary CCD camera on the astrograph, which is needed to continue currently NSF-funded research through grant AST-0908996, The Milky Way in 3D Velocity Space: A View from the Southern Hemisphere, by Casetti, van Altena, and Girard. That grant was funded under the American Recovery and Reinvestment Act (ARRA) of 2009 (Public Law 111-5).
Intellectual Merit: Dr. Casetti and her collaborators work on the Yale/San Juan Southern Proper Motion (SPM) survey. The astrometric observations have been ongoing for decades in order to accurately measure small stellar motions across the sky. The absolute proper motions of stars can be used to determine their orbits around the Galactic center. When such data are compared to dynamical simulations, models of Galaxy formation and evolution can be tested. Together with other observations these measurements are also used to learn about the gravitational potential of the Milky Way Galaxy.
Broader Impact: Measurements of the proper motions, positions and photographic photometry for globular clusters and areas along tidal streams and over-densities in the halo and thick disk are made publicly available on a webpage at Yale University. These huge data bases are a valuable resource to the astronomy community for studies of galactic kinematics and structure.
The repair of the cooling system will benefit more than one research project as other research group have use for the instrument. This is an international collaboration from researchers in Argentina and the US. Undergraduates at the Universities of San Juan, Cordoba and La Plata in Argentina will be trained as they obtain observations for the project.
The main goal of this grant was to repair the camera system of the Yale Southern Observatory in El Leoncito, Argentina. The 50-cm double astrograph together with its PixelVision 4Kx4K CCD represents the major facility with which Yale has conducted an all sky proper-motion and photometric survey. This survey has started over 40 years ago, and has benefited many NSF grants, including an existing ARAA grant. The purpose of the survey is the a comprehensive kinematical study of our galaxy, the Milky Way, and in 2011 it has released a catalog of 103 million stars. Many studies using these data have been published over the years and they include the study of the orbits of globular clusters, satellite galaxies of the Miky Way and of stars in the disk of the Galaxy. In January 2010, our camera system was unavailable for routine observations due to the failure of its Cryotiger cooling system. Thus a replacement cooling system was purchased from Brooks Automation, Inc. and installed in April 2011. Routine observation have resumed after test observations were first made. Thus, we are now able to continue our observations in particularly interesting regions of the Galaxy, regions that show presence of debris from satellites captured and destroyed by the gravitational field of the Milky Way.
