Thursday, January 24, 2013

lit: Asymmetric Drift and the Stellar Velocity ellipsoid

Asymmetric Drift and the Stellar Veloocity ellipsoid by Westfall, Bershady et al.:
The shape of the stellar velocity ellipsoid, defined by \sigma_R, \sigma_{phi}, and \sigma_z, provides key insights into the dynamical state of a galactic disk: \sigm_z:\sigma_R provides a measure of disk heating and  \sigma_{phi}:\sigma_R yields a check on the validity of the epicycle approximation (EA). Additionally, \sigma_R is a key component in measuring the stability criterion and in correcting rotation curves for asymmetric drift (AD), while \sigma_z is required for measuring the disk mass-to-light ratio.
See also p.2 on asymmetric drift corrections for stellar velocities.

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