Discovery of the First Low-luminosity Quasar at z > 7

Yoshiki Matsuoka, Masafusa Onoue, Nobunari Kashikawa, Michael A. Strauss, Kazushi Iwasawa, Chien Hsiu Lee, Masatoshi Imanishi, Tohru Nagao, Masayuki Akiyama, Naoko Asami, James Bosch, Hisanori Furusawa, Tomotsugu Goto, James E. Gunn, Yuichi Harikane, Hiroyuki Ikeda, Takuma Izumi, Toshihiro Kawaguchi, Nanako Kato, Satoshi KikutaKotaro Kohno, Yutaka Komiyama, Shuhei Koyama, Robert H. Lupton, Takeo Minezaki, Satoshi Miyazaki, Hitoshi Murayama, Mana Niida, Atsushi J. Nishizawa, Akatoki Noboriguchi, Masamune Oguri, Yoshiaki Ono, Masami Ouchi, Paul A. Price, Hiroaki Sameshima, Andreas Schulze, Hikari Shirakata, John D. Silverman, Naoshi Sugiyama, Philip J. Tait, Masahiro Takada, Tadafumi Takata, Masayuki Tanaka, Ji Jia Tang, Yoshiki Toba, Yousuke Utsumi, Shiang Yu Wang, Takuji Yamashita

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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 M 1450 = -24.13 0.08 mag and the bolometric luminosity is erg s -1 . 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 , thus indicating a moderate mass accretion rate with an Eddington ratio . 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.

Original languageEnglish (US)
Article numberL2
JournalAstrophysical Journal Letters
Volume872
Issue number1
DOIs
StatePublished - Feb 10 2019

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Dark ages
  • first stars
  • galaxies: active
  • galaxies: high-redshift
  • intergalactic medium
  • quasars: general
  • quasars: supermassive black holes
  • reionization

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    Matsuoka, Y., Onoue, M., Kashikawa, N., Strauss, M. A., Iwasawa, K., Lee, C. H., Imanishi, M., Nagao, T., Akiyama, M., Asami, N., Bosch, J., Furusawa, H., Goto, T., Gunn, J. E., Harikane, Y., Ikeda, H., Izumi, T., Kawaguchi, T., Kato, N., ... Yamashita, T. (2019). Discovery of the First Low-luminosity Quasar at z > 7. Astrophysical Journal Letters, 872(1), [L2]. https://doi.org/10.3847/2041-8213/ab0216