Power law correlations in galaxy distribution and finite volume effects from the Sloan Digital Sky Survey Data Release Four

Abstract

We discuss the estimation of galaxy correlation properties in several volume limited samples, in different sky regions, obtained from the Fourth Data Release of the Sloan Digital Sky Survey. The small scale properties are characterized through the determination of the nearest neighbor probability distribution. By using a very conservative statistical analysis, in the range of scales [0.5,~30] Mpc/h we detect power-law correlations in the conditional density in redshift space, with an exponent γ=1.0 \pm 0.1. This behavior is stable in all different samples we considered thus it does not depend on galaxy luminosity. In the range of scales [~30,~100] Mpc/h we find evidences for systematic unaveraged fluctuations and we discuss in detail the problems induced by finite volume effects on the determination of the conditional density. We conclude that in such range of scales there is an evidence for a smaller power-law index of the conditional density. However we cannot distinguish between two possibilities: (i) that a crossover to homogeneity (corresponding to γ=0 in the conditional density) occurs before 100 Mpc/h, (ii) that correlations extend to scales of order 100 Mpc/h (with a smaller exponent 0 < γ<1). We emphasize that galaxy distributions in these samples present large fluctuations at the largest scales probed, corresponding to the presence of large scale structures extending up to the boundaries of the present survey. Finally we discuss several differences between the behavior of the conditional density in mock galaxy catalogs built from cosmological N-body simulations and real data. We discuss some theoretical implications of such a fact considering also the super-homogeneous features of primordial density fields.

arXiv comment13 pages, 19 figures, to be publsihed in Astronomy and Astrophysics

References in corpus (15)

• Detection of the Baryon Acoustic Peak in the Large-Scale Correlation Function of SDSS Luminous Red Galaxies
• Spectroscopic Target Selection in the Sloan Digital Sky Survey: The Main Galaxy Sample
• Clustering of Galaxies in a Hierarchical Universe: I. Methods and Results at z=0
• The Luminosity and Color Dependence of the Galaxy Correlation Function
• The Luminosity Function of Galaxies in SDSS Commissioning Data
• Evolution of structure in cold dark matter universes
• On Departures From a Power Law in the Galaxy Correlation Function
• Cosmic homogeneity demonstrated with luminous red galaxies
• Statistical Physics for Cosmic Structures
• Basic properties of galaxy clustering in the light of recent results from the Sloan Digital Sky Survey
• On the streaming motions of haloes and galaxies
• Fractal correlations in the CfA2-South redshift survey
• Bias and the power spectrum beyond the turn-over
• Large scale correlations in galaxy clustering from the Two degree Field Galaxy Redshift Survey
• Growth of correlations in gravitational N-body simulations

Cited by in corpus (24)

• Light propagation in statistically homogeneous and isotropic dust universes
• Light propagation in statistically homogeneous and isotropic universes with general matter content
• The scale of homogeneity of the galaxy distribution in SDSS DR6
• Evaluating backreaction with the peak model of structure formation
• Absence of self-averaging and of homogeneity in the large scale galaxy distribution
• Applicability of the linearly perturbed FRW metric and Newtonian cosmology
• Inhomogeneities in the universe
• Very large scale correlations in the galaxy distribution
• Fractal Dimensions of a Weakly Clustered Distribution and the Scale of Homogeneity
• Breaking the self-averaging properties of spatial galaxy fluctuations in the Sloan Digital Sky Survey - Data Release Six
• Large-scale fluctuations in the distribution of galaxies from the Two Degree Field Galaxy Redshift Survey
• Galaxy distribution and extreme value statistics
• Testing homogeneity in the Sloan Digital Sky Survey Data Release Twelve with Shannon entropy
• Persistent fluctuations in the distribution of galaxies from the Two degree Field Galaxy Redshift Survey
• A method for testing the cosmic homogeneity with Shannon entropy
• Extension and estimation of correlations in Cold Dark Matter models
• An information theory based search for homogeneity on the largest accessible scale
• The complex universe: recent observations and theoretical challenges
• Probing large scale homogeneity and periodicity in the LRG distribution using Shannon entropy
• Fractal analysis of the large-scale stellar mass distribution in the Sloan Digital Sky Survey
• Wasserstein distance as a new tool for discriminating cosmologies through the topology of large scale structure
• Spatial density fluctuations and selection effects in galaxy redshift surveys
• Testing homogeneity of the galaxy distribution in the SDSS using Renyi entropy
• Scaling laws in the stellar mass distribution and the transition to homogeneity