AAS 203rd Meeting, January 2004
Session 115 Dwarf, Irregular and Starburst Galaxies
Poster, Thursday, January 8, 2004, 9:20am-4:00pm, Grand Hall

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[115.01] The Kinematics of LMC Red Supergiants

K.A.G. Olsen (NOAO/CTIO), P. Massey (Lowell Observatory)

We present analysis of radial velocities measured from a new sample of 167 red supergiants in the LMC. Our spectra, which were observed with the Hydra-CTIO multiobject spectrograph on the Blanco 4-m telescope, permit radial velocity accuracy of <1 km s-1. We combine our measurements with those of an additional 335 stars to study the kinematics of the LMC's young stellar population. We find a line-of-sight velocity dispersion of ~20 km s-1 about the kinematic model derived by van der Marel et la. (2002) for LMC carbon stars. Assigning stars into groups based on their spatial distribution and association with HI supershells and superbubbles, we find an average internal group velocity dispersion of ~10 km s-1. Finally, adopting either a kinematic model derived independently from the red supergiants or a kinematic model of the HI, we find a global velocity dispersion of ~13 km s-1. Our results suggest that the kinematics of the young stars follow that of the HI, that the HI kinematics are disturbed, and that past such disturbances are responsible for the observed velocity dispersion of the LMC's carbon stars.

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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.