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Constraining galactic structure parameters from a new extinction model and four star count samples
B. Chen 1,2,
F. Figueras 1,3,
J. Torra 1,3,
C. Jordi 1,3,
X. Luri 1,3 and
D. Galadí-Enríquez 1
Received 22 December 1998 / Accepted 1 November 1999
We propose a new 3-dimensional extinction model based on the COBE/IRAS all sky reddening map. Its application to globular and open cluster data evidences that the COBE/IRAS reddening map has an accuracy of 18%, but overestimates visual absorption by a factor of 1.16. This systematic error does not change with galactic latitude and opacity significantly.
The implementation of the new extinction model has optimized our galactic structure and kinematic model to low-galactic latitudes. Four star count samples distributed in different galactic directions have been compared with galactic model simulations. Numerical experiments allow us to constrain the radial distribution of the galactic disk. The disk scale length is found to be 2250 50 pc and the displacement of the Sun from the galactic plane = 27.5 6.0 pc.
Key words: ISM: dust, extinction Galaxy: globular clusters: general Galaxy: open clusters and associations: general methods: statistical astronomical data bases: miscellaneous Galaxy: solar neighbourhood
Send offprint requests to: B. Chen (email@example.com)
Online publication: December 2, 1999