A structure in the early universe at z ~ 1.3 that exceeds the homogeneity scale of the R-W concordance cosmology

TL;DR

This paper reports the discovery of an exceptionally large quasar group at redshift ~1.3, exceeding the homogeneity scale of standard cosmology, thus challenging the cosmological principle.

Contribution

It identifies the largest known structure in the early universe, providing evidence that may contradict the homogeneity assumption of the concordance cosmology.

Findings

Largest quasar group at z~1.3 identified

Structure size exceeds homogeneity scale

Challenges the cosmological principle

Abstract

A Large Quasar Group (LQG) of particularly large size and high membership has been identified in the DR7QSO catalogue of the Sloan Digital Sky Survey. It has characteristic size (volume^1/3) ~ 500 Mpc (proper size, present epoch), longest dimension ~ 1240 Mpc, membership of 73 quasars, and mean redshift <z> = 1.27. In terms of both size and membership it is the most extreme LQG found in the DR7QSO catalogue for the redshift range 1.0 <= z <= 1.8 of our current investigation. Its location on the sky is ~ 8.8 deg north (~ 615 Mpc projected) of the Clowes & Campusano LQG at the same redshift, <z> = 1.28, which is itself one of the more extreme examples. Their boundaries approach to within ~ 2 deg (~ 140 Mpc projected). This new, huge LQG appears to be the largest structure currently known in the early universe. Its size suggests incompatibility with the Yadav et al. scale of homogeneity for the concordance cosmology, and thus challenges the assumption of the cosmological principle.