Abstract

The stellar dynamics of ω[omega] Centauri are inferred from the radial velocities of 469 stars measured with CORAVEL (Mayor et al. 1997). Rather than fit the data to a family of models, we generate estimates of all dynamical functions nonparametrically, by direct operation on the data. The cluster is assumed to be oblate and edge-on but mass is not assumed to follow light. The mean motions are consistent with axisymmetry but the rotation is not cylindrical. The peak rotational velocity is 7.9 km s−1 at ∼ 11 pc from the center. The apparent rotation of ω[omega] Centauri is attributable in part to its proper motion. We reconstruct the stellar velocity ellipsoid as a function of position, assuming isotropy in the meridional plane. We find no significant evidence for a difference between the velocity dispersions parallel and perpendicular to the meridional plane. The mass distribution inferred from the kinematics is slightly more extended than, though not strongly inconsistent with, the luminosity distribution. We also derive the two-integral distribution function f(E, Lz) implied by the velocity data. (Refer to PDF file for exact formulas).

Publication Date

1997

Comments

Also archived in: arXiv:astro-ph/9612184 v1 18 Dec 1996 AND Rutgers Astrophysics Preprint Series No. 205 This work was supported by NSF grant AST 90-16515 and NASA grant NAG 5-2803 to DM.ISSN:1538-3881 Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

Document Type

Article

Department, Program, or Center

School of Physics and Astronomy (COS)

Campus

RIT – Main Campus

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