The Discovery of a Luminous Broad Absorption Line Quasar at a Redshift of 7.02

• Published in: Astrophysical journal. Letters 2018-12, Vol.869 (1), p.L9
• Main Authors: Wang, Feige, Yang, Jinyi, Fan, Xiaohui, Yue, Minghao, Wu, Xue-Bing, Schindler, Jan-Torge, Bian, Fuyan, Li, Jiang-Tao, Farina, Emanuele P., Bañados, Eduardo, Davies, Frederick B., Decarli, Roberto, Green, Richard, Jiang, Linhua, Hennawi, Joseph F., Huang, Yun-Hsin, Mazzucchelli, Chiara, McGreer, Ian D., Venemans, Bram, Walter, Fabian, Beletsky, Yuri
• Format: Article
• Language: English
• Subjects: Absorption; Active galactic nuclei; Bolometers; cosmology: observations; Dark energy; Deposition; early universe; Emission lines; Galaxies; galaxies: active; galaxies: high-redshift; Infrared astronomy; Infrared spectra; Ionization; Light speed; Luminosity; Near infrared radiation; Outflow; Quasars; quasars: individual (J0038-1527); Red shift; Sky surveys (astronomy); Space telescopes; Supermassive black holes; Velocity
• ISSN: 2041-8205; 2041-8213
• DOI: 10.3847/2041-8213/aaf1d2

Despite extensive efforts, to date only two quasars have been found at z > 7, due to a combination of low spatial density and high contamination from more ubiquitous Galactic cool dwarfs in quasar selection. This limits our current knowledge of the super-massive black hole growth mechanism and reionization history. In this Letter, we report the discovery of a luminous quasar at z = 7.021, DELS J003836.10-152723.6 (hereafter J0038-1527), selected using photometric data from Dark Energy Spectroscopic Instrument Legacy Imaging Survey, Pan-STARRS1 (PS1) imaging Survey, as well as Wide-field Infrared Survey Explore mid-infrared all-sky survey. With an absolute magnitude of M1450 = -27.1 and bolometric luminosity of LBol = 5.6 × 1013 L , J0038-1527 is the most luminous quasar known at z > 7. Deep optical to near-infrared spectroscopic observations suggest that J0038-1527 hosts a 1.3 billion solar mass black hole accreting at the Eddington limit, with an Eddington ratio of 1.25 0.19. The C iv broad emission line of J0038-1527 is blueshifted by more than 3000 km s−1 relative to the quasar systemic redshift. More detailed investigations of the high-quality spectra reveal three extremely high-velocity C iv broad absorption lines with velocity from 0.08 to 0.14 times the speed of light and total "balnicity" index of more than 5000 km s−1, suggesting the presence of relativistic outflows. J0038-1527 is the first quasar found at the epoch of reionization with such strong outflows, and therefore provides a unique laboratory to investigate active galactic nuclei feedback on the formation and growth of the most massive galaxies in the early universe.