Discovery of the First Low-Luminosity Quasar at z > 7
Abstract
We report the discovery of a quasar at z = 7.07, which was selected from the deep multi-band imaging data collected by the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. This quasar, HSC J124353.93+010038.5, has an order of magnitude lower luminosity than do the other known quasars at z > 7. The rest-frame ultraviolet absolute magnitude is M1450 = -24.13 +/- 0.08 mag and the bolometric luminosity is Lbol = (1.4 +/- 0.1) x 10^{46} erg/s. Its spectrum in the optical to near-infrared shows strong emission lines, and shows evidence for a fast gas outflow, as the C IV line is blueshifted and there is indication of broad absorption lines. The Mg II-based black hole mass is Mbh = (3.3 +/- 2.0) x 10^8 Msun, thus indicating a moderate mass accretion rate with an Eddington ratio 0.34 +/- 0.20. It is the first z > 7 quasar with sub-Eddington accretion, besides being the third most distant quasar, known to date. The luminosity and black hole mass are comparable to, or even lower than, those measured for the majority of low-z quasars discovered by the Sloan Digital Sky Survey, and thus this quasar likely represents a z > 7 counterpart to quasars commonly observed in the low-z universe.
Keywords
Cite
@article{arxiv.1901.10487,
title = {Discovery of the First Low-Luminosity Quasar at z > 7},
author = {Yoshiki Matsuoka and Masafusa Onoue and Nobunari Kashikawa and Michael A. Strauss and Kazushi Iwasawa and Chien-Hsiu Lee and Masatoshi Imanishi and Tohru Nagao and Masayuki Akiyama and Naoko Asami and James Bosch and Hisanori Furusawa and Tomotsugu Goto and James E. Gunn and Yuichi Harikane and Hiroyuki Ikeda and Takuma Izumi and Toshihiro Kawaguchi and Nanako Kato and Satoshi Kikuta and Kotaro Kohno and Yutaka Komiyama and Shuhei Koyama and Robert H. Lupton and Takeo Minezaki and Satoshi Miyazaki and Hitoshi Murayama and Mana Niida and Atsushi J. Nishizawa and Akatoki Noboriguchi and Masamune Oguri and Yoshiaki Ono and Masami Ouchi and Paul A. Price and Hiroaki Sameshima and Andreas Schulze and Hikari Shirakata and John D. Silverman and Naoshi Sugiyama and Philip J. Tait and Masahiro Takada and Tadafumi Takata and Masayuki Tanaka and Ji-Jia Tang and Yoshiki Toba and Yousuke Utsumi and Shiang-Yu Wang and Takuji Yamashita},
journal= {arXiv preprint arXiv:1901.10487},
year = {2019}
}
Comments
Accepted for publication in ApJ Letters