At its discovery, it was identified as the largest and the most massive known structure in the observable universe,[1][2][3] though it has been superseded by the Hercules–Corona Borealis Great Wall at 10 billion light-years.
Roger G. Clowes, together with colleagues from the University of Central Lancashire in Preston, United Kingdom, had reported on January 11, 2013 a grouping of quasars within the vicinity of the constellation Leo.
[5] Quasars are very luminous active galactic nuclei, thought to be supermassive black holes feeding on matter.
The Huge-LQG was initially named U1.27 due to its average redshift of 1.27 (where the "U" refers to a connected unit of quasars),[3] placing its distance at about 9 billion light-years from Earth.
After performing a number of statistical analyses on the quasar data, and finding extreme changes in the Huge-LQG membership and shape with small changes in the cluster finding parameters, he determined the probability that apparent clusters the size of the Huge-LQG would appear in a random assortment of quasars, by utilizing the similar friends-of-friends method originally used.
[10] The original method by Clowes produces at least a thousand clusterings identical to the Huge-LQG, even on regions where one should expect the distribution to be truly random.
Nevertheless, Clowes et al. found independent support for the reality of the structure from its coincidence with Mg II absorbers (once-ionised magnesium gas, commonly used to probe distant galaxies).