GLIMPSE360: Mapping the Galaxy's "Edge"
|Names||Robert A. Benjamin, B. Whitney, M. Meade, B. Babler, C. Watson, E. Churchwell, GLIMPSE360 team|
|Proceedings Title||Bulletin of the American Astronomical Society|
|Conference Name||American Astronomical Society, AAS Meeting #217, #241.14|
|Date||January 1, 2011|
|Library Catalog||NASA ADS|
|Abstract||We present compelling new evidence for the "truncation" of the Galactic stellar disk at R=13.4 ±0.4 kpc using data from the Spitzer Space Telescope's Warm Mission program GLIMPSE 360, a mid-infrared survey at 3.6 and 4.5 microns of the outer Galactic disk and warp, from galactic longitude l=65 to 265 degrees. The truncation is detected as a drop-off in the number of red giant stars per square degree fainter than a certain magnitude. Our average truncation distance is in excellent agreement with previous measurements of the truncation distance. By mapping the changing apparent magnitude of the dropoff as a function of Galactic longtiude, we are able to determine, for the first time, the variation in the truncation radius as a function of Galactic azimuth. Using TRILEGAL models of Galactic starcounts, we also constrain whether there is a sharp or more gradual dropoff in the density of the Galactic stellar disk beyond the truncation radius. This research was supported by NASA/JPL contract 1368014 and NASA ATP grant NNX10AI70G to the University of Wisconsin-Whitewater.|