Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-06-29
Astron.J.118:406-420,1999
Astronomy and Astrophysics
Astrophysics
18 pages, including 7 of 13 postscript figures. Figures 1-6 available at http://astro.caltech.edu/~pc. Accepted for publicatio
Scientific paper
10.1086/300930
HIRES on the Keck I telescope has been used to measure the first radial velocities for stars belonging to eleven, heavily-reddened globular clusters in the direction of the inner Galaxy. The question of kinematic substructuring among the Galactic globular cluster system is investigated using an updated catalog of globular cluster distances, metallicities and velocities. It is found that the population of metal-rich globular clusters shows significant rotation at all Galactocentric radii. For the metal-rich clusters within 4 kpc of the Galactic center, the measured rotation velocity and line-of-sight velocity dispersion are similar to those of bulge field stars. We investigate claims that the metal-rich clusters are associated with the central Galactic bar by comparing the kinematics of the innermost clusters to that of the atomic hydrogen in the inner Galaxy. The longitude-velocity diagram of both metal-rich and metal-poor clusters bears a remarkable similarity to that of the gas, including the same non-circular motions which have traditionally been interpreted as evidence for a Galactic bar, or, alternatively, a non-axisymmetric bulge. However, uncertainties in the existing three-dimensional Galactocentric positions for most of the clusters do not yet allow an unambiguous discrimination between the competing scenarios of membership in a rigidly rotating bar, or in a bulge which is an oblate isotropic rotator. We conclude that the majority of metal-rich clusters within the central 4 kpc of the Galaxy are probably associated with the bulge/bar, and not the thick disk. (ABRIDGED)
No associations
LandOfFree
Kinematics of the Galactic Globular Cluster System: New Radial Velocities for Clusters in the Direction of the Inner Galaxy does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Kinematics of the Galactic Globular Cluster System: New Radial Velocities for Clusters in the Direction of the Inner Galaxy, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Kinematics of the Galactic Globular Cluster System: New Radial Velocities for Clusters in the Direction of the Inner Galaxy will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-421924