Exploring Galactic Structure with the Fan Mountain Observatory Bench Spectrograph
Abstract
The Bench Spectrograph at the University of Virginia's Fan Mountain Observatory has recently seen first light through the facility's primary research telescope, the 1-meter astrometric reflector. As a single-object, fiber-fed instrument with moderate resolution (5-10 km s-1) capabilities, the spectrograph was motivated by several ongoing projects requiring stellar spectroscopy at the University of Virginia. The spectrograph was designed to supply moderate resolution Northern hemisphere spectra needed for the Grid Giant Star Survey (GGSS), which in addition to identifying candidates for the Astrometric Grid of NASA's Space Interferometry Mission (SIM), will provide a unique, unfilled all-sky catalog of low metallicity halo K giants that may be used to address a host of problems related to Galactic structure and kinematics. Because the GGSS candidate sample is extensive, bright (V<13), and uniformly distributed over the sky, a fiber-fed design was selected to provide maximal spectral stability and uniformity while optimizing observing efficiency. The spectrograph will be useful for observing stars brighter than V ∼14 throughout the optical spectrum. The instrument will also be used to estimate the dark matter content of the local Galactic disk by measuring dynamically the local disk volume density (the ``Oort limit'') reflected by the motions of a set of K giant ``tracers'' photometrically selected from a large-area survey of the North Galactic Pole. The Fan Mountain spectrograph will be used to refine our sample to the best possible homogeneity and to determine radial velocities. Once complete, this study should provide the largest and most reliable sample of dynamical ``Oort limit'' tracers assembled to date.
- Publication:
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American Astronomical Society Meeting Abstracts
- Pub Date:
- December 2003
- Bibcode:
- 2003AAS...20311206C