MAPPING THE ASYMMETRIC THICK DISK. I. A SEARCH FOR TRIAXIALITY
- Physics Department, United States Naval Academy, Annapolis, MD 21402 (United States)
- Department of Physics and Astronomy, Minnesota State University Moorhead, Moorhead, MN 56563 (United States)
A significant asymmetry in the distribution of faint blue stars in the inner Galaxy, Quadrant 1 (l = 20 deg. - 45 deg.) compared to Quadrant 4 was first reported by Larsen and Humphreys in 1996. Parker et al. greatly expanded the survey to determine its spatial extent and shape and the kinematics of the affected stars. This excess in the star counts was subsequently confirmed by Juric et al. using Sloan Digital Sky Survey data. Possible explanations for the asymmetry include a merger remnant, a triaxial thick disk, and a possible interaction with the bar in the disk. In this paper, we describe our program of wide field photometry to map the asymmetry to fainter magnitudes and therefore larger distances. To search for the signature of triaxiality, we extended our survey to higher Galactic longitudes. We find no evidence for an excess of faint blue stars at l {>=}55 deg. including the faintest magnitude interval. The asymmetry and star count excess in Quadrant 1 is thus not due to a triaxial thick disk.
- OSTI ID:
- 21301410
- Journal Information:
- Astronomical Journal (New York, N.Y. Online), Vol. 139, Issue 2; Other Information: DOI: 10.1088/0004-6256/139/2/348; Country of input: International Atomic Energy Agency (IAEA); ISSN 1538-3881
- Country of Publication:
- United States
- Language:
- English
Similar Records
MAPPING THE ASYMMETRIC THICK DISK. II. DISTANCE, SIZE, AND MASS OF THE HERCULES THICK DISK CLOUD
Galaxy evolution and large-scale structure in the far-infrared. I. IRAS pointed observations