Galaxy Clustering in Early Sloan Digital Sky Survey Redshift Data


Zehavi I, Blanton MR, Frieman JA, Weinberg DH, Mo HJ, Strauss MA, Anderson SF, Annis J, Bahcall NA, Bernardi M, et al. Galaxy Clustering in Early Sloan Digital Sky Survey Redshift Data. The Astrophysical Journal. 2002;571 :172-190.

Date Published:

May 1, 2002


We present the first measurements of clustering in the Sloan Digital SkySurvey (SDSS) galaxy redshift survey. Our sample consists of 29,300galaxies with redshifts5700kms-1<=cz<=39,000kms-1, distributed inseveral long but narrow (2.5d-5°) segments, covering 690deg2. For the full, flux-limited sample, the redshift-spacecorrelation length is approximately 8 h-1 Mpc. Thetwo-dimensional correlation function ξ(rp,π) showsclear signatures of both the small-scale, ``fingers-of-God'' distortioncaused by velocity dispersions in collapsed objects and the large-scalecompression caused by coherent flows, though the latter cannot bemeasured with high precision in the present sample. The inferredreal-space correlation function is well described by a power law,ξ(r)=(r/6.1+/-0.2h-1Mpc)-1.75+/-0.03, for0.1h-1Mpc<=r<=16h-1Mpc. The galaxy pairwisevelocity dispersion is σ12~600+/-100kms-1for projected separations0.15h-1Mpc<=rp<=5h-1Mpc. When wedivide the sample by color, the red galaxies exhibit a stronger andsteeper real-space correlation function and a higher pairwise velocitydispersion than do the blue galaxies. The relative behavior ofsubsamples defined by high/low profile concentration or high/low surfacebrightness is qualitatively similar to that of the red/blue subsamples.Our most striking result is a clear measurement of scale-independentluminosity bias at r<~10h-1Mpc: subsamples with absolutemagnitude ranges centered on M*-1.5, M*, andM*+1.5 have real-space correlation functions that areparallel power laws of slope ~-1.8 with correlation lengths ofapproximately 7.4, 6.3, and 4.7 h-1 Mpc, respectively.