Kinematic response of the outer stellar disk to a central bar

被引:41
作者
Mühlbauer, G
Dehnen, W
机构
[1] Max Planck Inst Astron, D-69117 Heidelberg, Germany
[2] Astrophys Inst Potsdam, D-14482 Potsdam, Germany
关键词
Galaxy : disk; Galaxy : kinematics and dynamics; solar neighbourhood; Galaxy : fundamental parameters Galaxy : structure;
D O I
10.1051/0004-6361:20030186
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We study, using direct orbit integrations, the kinematic response of the outer stellar disk to the presence of a central bar, as in the Milky-Way. We find that the bar's outer Lindblad resonance (OLR) causes significant perturbations of the velocity moments. With increasing velocity dispersion, the radius of these perturbations is shifted outwards, beyond the nominal position of the OLR, but also the disk becomes less responsive. If we follow Dehnen (2000) in assuming that the OLR occurs just inside the Solar circle and that the Sun lags the bar major axis by similar to20degrees, we find ( 1) no significant radial motion of the local standard of rest (LSR), (2) a vertex deviation of similar to10degrees and ( 3) a lower ratio sigma(2)(2)/sigma(1)(2) of the principal components of the velocity-dispersion tensor than for an unperturbed disk. All of these are actually consistent with the observations of the Solar-neighbourhood kinematics. Thus it seems that at least the lowest-order deviations of the local-disk kinematics from simple expectations based on axisymmetric equilibrium can be attributed entirely to the influence of the galactic bar.
引用
收藏
页码:975 / 984
页数:10
相关论文
共 12 条
[1]  
Binney J., 1998, PR S ASTROP
[2]  
Binney J., 2008, Galactic Dynamics
[3]   The distribution of nearby stars in velocity space inferred from Hipparcos data [J].
Dehnen, W .
ASTRONOMICAL JOURNAL, 1998, 115 (06) :2384-2396
[4]   Local stellar kinematics from Hipparcos data [J].
Dehnen, W ;
Binney, JJ .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1998, 298 (02) :387-394
[5]   The effect of the outer Lindblad resonance of the Galactic bar on the local stellar velocity distribution [J].
Dehnen, W .
ASTRONOMICAL JOURNAL, 2000, 119 (02) :800-812
[6]   Simple distribution functions for stellar disks [J].
Dehnen, W .
ASTRONOMICAL JOURNAL, 1999, 118 (03) :1201-1208
[7]   Three-dimensional structure of the Milky Way disk:: The distribution of stars and dust beyond 0.35 R⊙ [J].
Drimmel, R ;
Spergel, DN .
ASTROPHYSICAL JOURNAL, 2001, 556 (01) :181-202
[8]   SIMPLE DISKS WITH FLAT ROTATION CURVES [J].
EVANS, NW ;
COLLETT, JL .
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 1993, 264 (02) :353-374
[9]   Order and chaos in the local disc stellar kinematics induced by the Galactic bar [J].
Fux, R .
ASTRONOMY & ASTROPHYSICS, 2001, 373 (02) :511-535
[10]   Stellar halo parameters from 4588 subdwarfs [J].
Gould, A .
ASTROPHYSICAL JOURNAL, 2003, 583 (02) :765-775