Clustering of K-band selected local galaxies

Abstract

We present a detailed clustering analysis of a large K-band selected local galaxy sample, which is constructed from the 2MASS and the SDSS and consists of 82486 galaxies with 10 < K < 13.5 and 0.01 < z < 0.1. The two-point correlation function of the magnitude-limited sample in real space at small scales is well described by the power law ζ(r) (r/6.44 0.23) -1.81 0.02. The pairwise velocity dispersion is derived from the anisotropic two-point correlation function and we find the dispersion σ12 685 17 kms-1 if scale invariance is assumed, which is larger than values measured in the optical bands of the selected galaxy samples. We further investigate the dependence of the two-point correlation function and the σ 12 on the g - r color and the K-band luminosity, and obtain similar results to previous works in optical bands. Comparing a mock galaxy sample with our real data indicates that the semi-analytical model cannot mimic the σ12 in observation, although it can approximate the two-point correlation function within measurement uncertainties. © 2009 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd.