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: http://www.stsci.edu/~marel/abstracts/abs_R5.html
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Model calculations for the outer parts of spherical galaxies yield line profiles that can deviate significantly from Gaussians. Even for models with only mild velocity dispersion anisotropy the RMS deviations from a Gaussian can be of order 10%. Approximating these line profiles by Gaussians yields systematic errors in the estimates of the mean radial velocity and velocity dispersion of 10% or more.
The new method is used to derive line profiles for the elliptical
galaxies IC 1459, NGC 1374 and NGC 4278. All three galaxies have
asymmetric line profiles on the major axis, similar to those found
earlier in galaxies with kinematically distinct cores. In addition we
find evidence for symmetric deviations from a Gaussian. By fitting
Gaussians to these asymmetric line profiles the amplitude of the
rotation curve can be overestimated by 30% or more. The results for
h_3 and h_4 are not strongly dependent on the spectral resolution of
the observations. The results confirm the notion that elliptical
galaxies have complex structures, due to their complex formation
history. It is expected that accurate measurements of line profiles
will provide additional constraints on models of galaxy structure and
formation.