Excess Clustering on Large Scales in the MegaZ DR7 Photometric Redshift Survey

Abstract

We observe a large excess of power in the statistical clustering of Luminous Red Galaxies in the photometric SDSS galaxy sample called MegaZ DR7. This is seen over the lowest multipoles in the angular power spectra C_{\ell} in four equally spaced redshift bins between 0.45 < z < 0.65. However, it is most prominent in the highest redshift band at ~ 4 sigma and it emerges at an effective scale k ~ 0.01 h Mpc^{-1}. Given that MegaZ DR7 is the largest cosmic volume galaxy survey to date (3.3 (Gpc h^{-1})^3) this implies an anomaly on the largest physical scales probed by galaxies. Alternatively, this signature could be a consequence of it appearing at the most systematically susceptible redshift. There are several explanations for this excess power that range from systematics to new physics. This could have important consequences for the next generation of galaxy surveys or the LCDM model. We test the survey, data and excess power, as well as possible origins.

4 pages, 3 figures

References in corpus (6)

• The imprints of primordial non-gaussianities on large-scale structure: scale dependent bias and abundance of virialized objects
• The 2dF-SDSS LRG and QSO (2SLAQ) Luminous Red Galaxy Survey
• Cosmological baryonic and matter densities from 600,000 SDSS Luminous Red Galaxies with photometric redshifts
• Precision cosmology defeats void models for acceleration
• MegaZ-LRG: A photometric redshift catalogue of one million SDSS Luminous Red Galaxies
• Can a galaxy redshift survey measure dark energy clustering?

Cited by in corpus (4)

• The significance of the integrated Sachs-Wolfe effect revisited
• The VLT LBG Redshift Survey - III. The clustering and dynamics of Lyman-break galaxies at z ~ 3
• Tomography of the Fermi-LAT gamma-ray diffuse extragalactic signal via cross-correlations with galaxy catalogs
• Effect of training characteristics on object classification: an application using Boosted Decision Trees