1997/11/06 by G. A. Drukier, S. D. Slavin, H. N. Cohn +6 · 1 citation
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astronomy and Astrophysical Research #Astrophysics #Classical mechanics #Cluster (spacecraft) #Dispersion (optics) #Galaxy #Geometry #Globular cluster #Kinematics #Magnitude (astronomy) #Optics #Physics #Position (finance) #Position angle #RADIUS #Rotation (mathematics) #Stars #Stellar, planetary, and galactic studies #Velocity dispersion #astro-ph
paper · pdf · doi:10.1086/300231
32 pages, LaTeX, includes 13 eps figures, 5 tables are in external tex files, to appear in Feb 1998 AJ
arxiv created 1997/11/06 · openalex publication_date 1998/02/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present velocities for 230 stars in the outer parts of the globular cluster M15 measured with the Hydra multifiber spectrograph on the 3.5 m WIYN telescope. A new Bayesian technique is used for analyzing the data. The mean velocity of the cluster is -106.9 ± 0.3 km s -1 . Rotation with an amplitude of 1.5 ± 0.4 km s -1 and a position angle of 125° ± 19° is observed, and a model including rotation is marginally favored over one without rotation. The velocity dispersion decreases from the center out to about 7' and then appears to increase slightly. This behavior is strikingly different from the continued decline of velocity dispersion with increasing radius that is expected in an isolated cluster. We interpret this as an indication of heating of the outer part of M15 by the Galactic tidal field.