High-Velocity Molecular Gas in the Galactic Center Radio Lobe

We point out a possible association of high-velocity molecular gas with the Galactic Center Radio Lobe (GCL). A molecular spur in the eastern GCL ridge is receding at \Vlsr \sim +100 \kms, and the western spur approaching at \Vlsr \sim -150 \kms, suggesting a high-velocity rotation of the GCL. We study the kinematics of the GCL based on these molecular line data.Comment: To appear in ApJ. Letters, Plain TeX, Figures on reques

Accuracy Diagrams for the Galactic Rotation Curve and Kinematical Distances

We revisit the methods to determine the Galactic rotation curve and kinematical distances from radial velocities and proper motions. We construct "accuracy diagrams" to show the distributions in the galactic plane of expected uncertainties in the derived quantities such as rotation velocities and kinematical distances. We discuss how to optimize the source selection for measurements of kinematical quantities based on the accuracy diagrams.Comment: 9 pages, 12 figures, PASJ accepte

Dark Bulge, Exponential Disk, and Massive Halo in the Large Magellanic Cloud

The rotation curve of the Large Magellanic Cloud, which we have derived from high-resolution HI position-velocity diagrams observed by Kim et al (1998), shows a steep central rise and flat rotation with a gradual rise toward the edge. Using the rotation curve, we have calculated the distribution of surface mass density, and show that the LMC has a dark compact bulge, an exponential disk, and a massive halo. The bulge is 1.2 kpc away from the center of the stellar bar, and is not associated with an optical counterpart. This indicates that the "dark bulge" has a large fraction of dark matter, with an anomalously high mass-to-luminosity (M/L) ratio. On the contrary, the stellar bar has a smaller M/L ratio compared to the surrounding regions. (http://www.ioa.s.u-tokyo.ac.jp/~sofue/99lmc.htm)Comment: PASJ 1999 in press, Latex with Postscript figure