Distribution functions for evolved stars in the inner galactic plane

被引:0
|
作者
Sevenster, MN
Dejonghe, H
Van Caelenberg, K
Habing, HJ
机构
[1] Sterrenkundig Observ, B-9000 Ghent, Belgium
[2] Sterrewacht Leiden, NL-2300 RA Leiden, Netherlands
来源
ASTRONOMY & ASTROPHYSICS | 2000年 / 355卷 / 02期
关键词
Galaxy : kinematics and dynamics; Galaxy : stellar content; Galaxy : structure; stars : AGB and post-AGB;
D O I
暂无
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present dynamical distribution functions for a homogeneous sample of oxygen-rich, evolved, intermediate-mass stars in the inner galactic plane. We use an axisymmetric, two-component Stackel potential that satisfies recent constraints on the galactic potential, amongst others a slightly declining local rotation curve. We show that this potential is adequate to model stellar-kinematic samples with radial extent ranging from similar to 100 pc to similar to 5 kpc in the Galaxy. The stable two-integral model that gives the best fit to the first three projected moments provides a very good global representation of the data but fails to reproduce the central line-of-sight dispersion, the central apparent scaleheight and the almost-cylindrical rotation at intermediate longitudes (5 degrees < \l\ < 15 degrees). All these features, indicative of the galactic Bar, are fitted well by a three-integral model. We discuss various properties of the two- and three-integral distribution functions and the implications for galactic structure. A somewhat thicker disk component is needed to explain the observed distribution of older AGE stars in the plane; this component at the same time fits the kinematics of AGB stars at higher latitudes better than the thinner disk. We find that the Disk and the Bulge, as traced by AGE stars, are very similar dynamically and could well be one and the same component. There is a dynamically distinct component in the inner 100 pc of the Bulge, however.
引用
收藏
页码:537 / 551
页数:15
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