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Persistent URL http://purl.org/net/epubs/work/10789472
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Record Id 10789472
Title The 2dF Galaxy Redshift Survey: The nature of the relative bias between galaxies of different spectral type
Abstract We present an analysis of the relative bias between early- and late-type galaxies in the Two-degree Field Galaxy Redshift Survey (2dFGRS) - as defined by the ? parameter of Madgwick et al., which quantifies the spectral type of galaxies in the survey. We calculate counts in cells for flux-limited samples of early- and late-type galaxies, using approximately cubical cells with sides ranging from 7 to 42 h Mpc. We measure the variance of the counts in cells using the method of Efstathiou et al., which we find requires a correction for a finite volume effect equivalent to the integral constraint bias of the autocorrelation function. Using a maximum-likelihood technique we fit lognormal models to the one-point density distribution, and develop methods of dealing with biases in the recovered variances resulting from this technique. We then examine the joint density distribution function, f(? , ? ), and directly fit deterministic bias models to the joint counts in cells. We measure a linear relative bias of ?1.3, which does not vary significantly with ?. A deterministic linear bias model is, however, a poor approximation to the data, especially on small scales (? ? 28 h Mpc) where deterministic linear bias is excluded at high significance. A power-law bias model with index b ? 0.75 is a significantly better fit to the data on all scales, although linear bias becomes consistent with the data for ? ? 40 h Mpc.
Organisation CCLRC , SSTD , SSTD-IS
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Language English (EN)
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Journal Article Mon Notic Roy Astron Soc 356, no. 2 (2005): 456-474. doi:10.1111/j.1365-2966.2004.08446.x 2005