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D. H. Weinberg (Ohio State University)
We are now obtaining measurements of galaxy clustering in the local universe that are unprecedented in detail and precision, from the 2dF Galaxy Redshift Survey and the Sloan Digital Sky Survey (SDSS). The principal obstacle to testing cosmological models against these measurements is the expectation that galaxies are, at least to some degree, biased tracers of the underlying mass distribution. I will discuss the problem of bias in the context of the halo occupation distribution (HOD), which characterizes the relation between galaxies and mass by the probability distribution P(N|M) that a halo of virial mass M contains N galaxies, together with prescriptions that specify the relative spatial and velocity distributions of galaxies and dark matter within halos. Different galaxy clustering statistics have complementary sensitivities to aspects of the HOD and of the cosmological model, so with a sufficient set of high-precision measurements one can simultaneously test the predictions of galaxy formation models and constrain cosmological parameters that give leverage on the nature of dark energy and the physics of inflation. I will present some of the initial results of this program based on measurements from the SDSS, including the dependence of HODs on galaxy luminosity and color and constraints on the matter density parameter and the amplitude of mass fluctuations.
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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.