IAU00383
Presentation type requested: POSTER
THE STRUCTURE AND VELOCITY FIELD OF THE LOCAL SUPERCLUSTER
Karen L Masters
Cornell University
There are now several hundred galaxies with published distances from primary indicators (eg. Cepheid, TRGB etc), that are accurate within 5-10%. These galaxies provide a firm basis for study of the structure of the local universe. We will combine them with the recently completed SF2 Tully-Fisher sample, containing over a thousand spiral galaxies within cz=4000km/s, to investigate the local supercluster (LSC). In the LSC, redshifts are dominated by peculiar motions. Therefore having a model to correct for this is necessary to relate redshifts to distances. A parametric model will be investigated, which includes spherical infall onto Virgo, other spherical attractors, and the effects of thermal and virial velocity dispersion. Parametric models have been applied to the velocity field in the LSC many times before, often providing quite different answers. With the sample that will be constructed, we hope to provide the best possible parametric model for use in deriving distances. There is substantial evidence that many clusters are not spherically symmetric, so the validity of spherical infall models has been called into question. This will be investigated (including possible elongation of Virgo along the line of sight) in deviations from the model.
Haynes Martha P
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