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Paper: Application of Discrete Radial Velocity Fields to Map the Dynamics of Elliptical Outer Halos
Volume: 230, Galaxy Disks and Disk Galaxies
Page: 561
Authors: Napolitano, N. R.; Arnaboldi, M.; Capaccioli, M.
Abstract: The kinematics of E and S0 outer regions is fundamental to test the recent theories in galaxies formation (Fukugita, Hogan & Peebles 1996), to measure the amount of dark matter and find evidences for interaction. Globular clusters and planetary nebulae are very useful kinematical tracers because they allow kinematical measurements at large distances (>2Re) from galaxy centers where the integrated light techniques fail. However, the use of their discrete radial velocity fields suffers from some limitations: 1) the line-of-sight stellar kinematics in E galaxies cannot be directly related to intrinsic quantities without some prior knowledge of the real internal dynamics; 2) so far with 4-m telescopes it has been possible to acquire only limited sample with up to 50 radial velocities for giant Es and S0s (Arnaboldi et al. 1998). In this framework we wish to address the following questions: whether it is possible to re-build the actual projected kinematics of spherical systems starting from these small samples, and whether hypotheses on the internal rotation structure introduce some biases on the kinematical estimates.
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