A luminous quasar at a redshift of z = 7.085
Abstract
The intergalactic medium was not completely reionized until approximately a billion years after the Big Bang, as revealed by observations of quasars with redshifts of less than 6.5. It has been difficult to probe to higher redshifts, however, because quasars have historically been identified in optical surveys, which are insensitive to sources at redshifts exceeding 6.5. Here we report observations of a quasar (ULAS J112001.48+064124.3) at a redshift of 7.085, which is 0.77 billion years after the Big Bang. ULAS J1120+0461 had a luminosity of 6.3x10^13 L_Sun and hosted a black hole with a mass of 2x10^9 M_Sun (where L_Sun and M_Sun are the luminosity and mass of the Sun). The measured radius of the ionized near zone around ULAS J1120+0641 is 1.9 megaparsecs, a factor of three smaller than typical for quasars at redshifts between 6.0 and 6.4. The near zone transmission profile is consistent with a Ly alpha damping wing, suggesting that the neutral fraction of the intergalactic medium in front of ULAS J1120+0641 exceeded 0.1.
Keywords
Cite
@article{arxiv.1106.6088,
title = {A luminous quasar at a redshift of z = 7.085},
author = {Daniel J. Mortlock and Stephen J. Warren and Bram P. Venemans and Mitesh Patel and Paul C. Hewett and Richard G. McMahon and Chris Simpson and Tom Theuns and Eduardo A. Gonzales-Solares and Andy Adamson and Simon Dye and Nigel C. Hambly and Paul Hirst and Mike J. Irwin and Ernst Kuiper and Andy Lawrence and Huub J. A. Rottgering},
journal= {arXiv preprint arXiv:1106.6088},
year = {2011}
}
Comments
5 pages, 4 figures; source data available at http://astro.ic.ac.uk/~mortlock/ulas_j1120+0641/