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Unformatted text preview: power spectra scale as b 2 . Since in a simple approximation, the growth rate of mass perturbations scales with the mass contribution to the cosmic density as M 0.6 , one often encounters the combination (called the redshift distortion parameter) = M 0.6 b in studies trying to solve derived density fields and galaxy distributions for b . This has the interesting property that structure amplitudes in redshift space are enhanced by a factor (1+) over those in linear coordinate space. Hamilton's review (reference above) is a nice compendium of the density-velocity field connection, showing that values of from 0.5 to 1 are allowed by existing surveys. To confuse matters somewhat, some papers use a bias parameter that runs inversely to this convention. Analysis of the 2dF galaxy survey suggests that bias is not important on scales 5-30 Mpc (Verde et al. 2002 MNRAS 335, 432), with a fitted linear bias parameter of 1.04 0.11 and quadratic term -0.05 0.08. On these scales (at least), both angular and redshift clustering suggest that term -0....
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- Fall '10