2018年12月20日
Subaru High-z Exploration of Low-luminosity Quasars (SHELLQs). V. Quasar Luminosity Function and Contribution to Cosmic Reionization at z = 6
The Astrophysical Journal
- 巻
- 869
- 号
- 2
- 開始ページ
- 150
- 終了ページ
- 150
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.3847/1538-4357/aaee7a
- 出版者・発行元
- American Astronomical Society
We present new measurements of the quasar luminosity function (LF) at z similar to 6 over an unprecedentedly wide range of the rest-frame ultraviolet luminosity M-1450 from -30 to -22 mag. This is the fifth in a series of publications from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, which exploits the deep multiband imaging data produced by the Hyper Suprime-Cam Subaru Strategic Program survey. The LF was calculated with a complete sample of 110 quasars at 5.7 <= z <= 6.5, which includes 48 SHELLQs quasars discovered over 650 deg(2) and 63 brighter quasars discovered by the Sloan Digital Sky Survey and the Canada-France-Hawaii Quasar Survey (including one overlapping object). This is the largest sample of z similar to 6 quasars with a well-defined selection function constructed to date, which has allowed us to detect significant flattening of the LF at its faint end. A double power-law function fit to the sample yields a faint-end slope alpha = -1.23(-0.34)(+0.44), a bright-end slope beta = -2.73(-0.31)(+0.23), a break magnitude M*(1450) = -24.90(-0.90)(+0.75), and a characteristic space density Phi* = 10.9(-6.8)(+10.0) Gpc(-3) mag(-1). Integrating this best-fit model over the range -18 < M-1450 < -30 mag, quasars emit ionizing photons at the rate of <(n)over dot>(ion) = 10(48.8 +/- 0.1) s(-1) Mpc(-3) at z = 6.0. This is less than 10% of the critical rate necessary to keep the intergalactic medium ionized, which indicates that quasars are not a major contributor to cosmic reionization.
- リンク情報
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- DOI
- https://doi.org/10.3847/1538-4357/aaee7a
- Web of Science
- https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000454219200006&DestApp=WOS_CPL
- URL
- http://stacks.iop.org/0004-637X/869/i=2/a=150/pdf
- URL
- http://stacks.iop.org/0004-637X/869/i=2/a=150?key=crossref.2c0b86f4dd34fe0fa70ad5769dd5c994
- ID情報
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- DOI : 10.3847/1538-4357/aaee7a
- ISSN : 0004-637X
- eISSN : 1538-4357
- Web of Science ID : WOS:000454219200006