Huge-LQG

The Huge Large Quasar Group, (Huge-LQG, also called U1.27) is a possible structure or pseudo-structure of 73 quasars, referred to as a large quasar group, that measures about 4 billion light-years across. At its discovery, it was identified as the largest and the most massive known structure in the observable universe, though it has been superseded by the Hercules-Corona Borealis Great Wall at 10 billion light-years. There are also issues about its structure (see Dispute section below).

Roger G. Clowes, together with colleagues from the University of Central Lancashire in Preston, United Kingdom, has reported on January 11, 2013 a grouping of quasars within the vicinity of the constellation Leo. They used data from the DR7QSO catalogue of the comprehensive Sloan Digital Sky Survey, a major multi-imaging and spectroscopic redshift survey of the sky. They reported that the grouping was, as they announced, the largest known structure in the observable universe. The structure was initially discovered in November 2012 and took two months of verification before its announcement. News about the structure's announcement spread worldwide, and has received great attention on the scientific community.

The Huge-LQG was estimated to be about 1.24 Gpc in length, by 640 Mpc and 370 Mpc on the other dimensions, and contains 73 quasars, respectively. Quasars are very luminous active galactic nuclei, thought to be supermassive black holes feeding on matter. Since they are only found in dense regions of the universe, quasars can be used to find overdensities of matter within the universe. It has the approximate binding mass of 6.1×10¹⁸ (6.1 trillion (long scale) or 6.1 quintillion (short scale)) M_☉. The Huge-LQG was initially named U1.27 due to its average redshift of 1.27, placing its distance at about 9 billion light-years from Earth.

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