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C.M. Springob, M.P. Haynes, R. Giovanelli (Cornell U.)
The Pisces-Perseus Supercluster (PPS) is one of the most prominent features of large-scale structure in the local universe. It represents a significant projected overdensity and exhibits clear signs of filamentary structure. The proximity (4500 < vhelio < 5500 km/s) and orientation (nearly perpendicular to the line of sight) of the PPS main ridge make it an ideal target for peculiar velocity studies. Previous studies of the peculiar velocity field of PPS have claimed evidence for infall though with low statistical significance. We make use of a new all-sky Tully-Fisher survey, SFI++, including over 900 galaxies with Tully-Fisher distances in the PPS region (22 < \alpha < 4 hours, -10 < \delta < 50 degrees, 3000 < vhelio < 9000 km/s). The sample will be combined with others available in the literature, such as the ENEAR and EFAR datasets, and comparison will be made with the density field derived from redshifts alone for some 3000 galaxies in the same region. We make use of averaging within groups and clusters to reduce noise in the velocity field. A sample of this size and completeness should be sufficient to show clear evidence of both foreground and background infall onto the supercluster ridge. It will also allow us to test the hypothesis that the galaxy field traces the mass density field with greater precision than previous studies, and to test for variation of the bias parameter b among subsamples of varying peculiar velocity, local density, and spatial location. We report on the results of an initial investigation aimed at determining how sensitive our peculiar velocity catalog will be to such variations in galaxy biasing, using a simple model for such variations and comparing simulated observations to the PSCz density reconstruction (Branchini et al. 1999).
This work is partially funded by NSF grants AST-9900695 and AST-0098526.
The author(s) of this abstract have provided an email address for comments about the abstract: springob@astro.cornell.edu
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Bulletin of the American Astronomical Society, 35#5
© 2003. The American Astronomical Soceity.