TY - JOUR
T1 - Quasar Luminosity Function at z = 7
AU - Matsuoka, Yoshiki
AU - Onoue, Masafusa
AU - Iwasawa, Kazushi
AU - Strauss, Michael A.
AU - Kashikawa, Nobunari
AU - Izumi, Takuma
AU - Nagao, Tohru
AU - Imanishi, Masatoshi
AU - Akiyama, Masayuki
AU - Silverman, John D.
AU - Asami, Naoko
AU - Bosch, James
AU - Furusawa, Hisanori
AU - Goto, Tomotsugu
AU - Gunn, James E.
AU - Harikane, Yuichi
AU - Ikeda, Hiroyuki
AU - Inayoshi, Kohei
AU - Ishimoto, Rikako
AU - Kawaguchi, Toshihiro
AU - Kikuta, Satoshi
AU - Kohno, Kotaro
AU - Komiyama, Yutaka
AU - Lee, Chien Hsiu
AU - Lupton, Robert H.
AU - Minezaki, Takeo
AU - Miyazaki, Satoshi
AU - Murayama, Hitoshi
AU - Nishizawa, Atsushi J.
AU - Oguri, Masamune
AU - Ono, Yoshiaki
AU - Oogi, Taira
AU - Ouchi, Masami
AU - Price, Paul A.
AU - Sameshima, Hiroaki
AU - Sugiyama, Naoshi
AU - Tait, Philip J.
AU - Takada, Masahiro
AU - Takahashi, Ayumi
AU - Takata, Tadafumi
AU - Tanaka, Masayuki
AU - Toba, Yoshiki
AU - Wang, Shiang Yu
AU - Yamashita, Takuji
N1 - Funding Information:
The HSC collaboration includes the astronomical communities of Japan and Taiwan, and Princeton University. The HSC instrumentation and software were developed by the National Astronomical Observatory of Japan (NAOJ), the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), the University of Tokyo, the High Energy Accelerator Research Organization (KEK), the Academia Sinica Institute for Astronomy and Astrophysics in Taiwan (ASIAA), and Princeton University. Funding was contributed by the FIRST program from the Japanese Cabinet Office, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Japan Society for the Promotion of Science (JSPS), Japan Science and Technology Agency (JST), the Toray Science Foundation, NAOJ, Kavli IPMU, KEK, ASIAA, and Princeton University.
Funding Information:
The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg, and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen’s University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation.
Funding Information:
Y.M. was supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI grant Nos. 17H04830, 21H04494, and the Mitsubishi Foundation grant No. 30140. M.O. and K.I. are supported by the National Natural Science Foundation of China (12073003, 11991052, 11721303, 12150410307, 11950410493) and the China Manned Space Project Nos. CMS-CSST-2021-A04 and CMS-CSST-2021-A06. K.I. acknowledges support by grant PID2019-105510GB-C33 funded by MCIN/AEI/10.13039/501100011033 and “Unit of excellence María de Maeztu 2020–2023” awarded to ICCUB (CEX2019-000918-M).
Publisher Copyright:
© 2023. The Author(s). Published by the American Astronomical Society.
PY - 2023/6/1
Y1 - 2023/6/1
N2 - We present the quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars at 6.55 < z < 7.15. The sample of 22 quasars from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, combined with 13 brighter quasars in the literature, covers an unprecedentedly wide range of rest-frame ultraviolet magnitudes over -28 < M 1450 < -23. We found that the binned LF flattens significantly toward the faint end populated by the SHELLQs quasars. A maximum likelihood fit to a double power-law model has a break magnitude M1450∗=-25.60-0.30+0.40, a characteristic density φ∗=1.35-0.30+0.47 Gpc-3 mag-1, and a bright-end slope β=-3.34-0.57+0.49, when the faint-end slope is fixed to α = -1.2 as observed at z ≤ 6. The overall LF shape remains remarkably similar from z = 4 to 7, while the amplitude decreases substantially toward higher redshifts, with a clear indication of an accelerating decline at z ≥ 6. The estimated ionizing photon density, 1048.2±0.1 s-1 Mpc-3, is less than 1% of the critical rate to keep the intergalactic medium ionized at z = 7, and thus indicates that quasars are not a major contributor to cosmic reionization.
AB - We present the quasar luminosity function (LF) at z = 7, measured with 35 spectroscopically confirmed quasars at 6.55 < z < 7.15. The sample of 22 quasars from the Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs) project, combined with 13 brighter quasars in the literature, covers an unprecedentedly wide range of rest-frame ultraviolet magnitudes over -28 < M 1450 < -23. We found that the binned LF flattens significantly toward the faint end populated by the SHELLQs quasars. A maximum likelihood fit to a double power-law model has a break magnitude M1450∗=-25.60-0.30+0.40, a characteristic density φ∗=1.35-0.30+0.47 Gpc-3 mag-1, and a bright-end slope β=-3.34-0.57+0.49, when the faint-end slope is fixed to α = -1.2 as observed at z ≤ 6. The overall LF shape remains remarkably similar from z = 4 to 7, while the amplitude decreases substantially toward higher redshifts, with a clear indication of an accelerating decline at z ≥ 6. The estimated ionizing photon density, 1048.2±0.1 s-1 Mpc-3, is less than 1% of the critical rate to keep the intergalactic medium ionized at z = 7, and thus indicates that quasars are not a major contributor to cosmic reionization.
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U2 - 10.3847/2041-8213/acd69f
DO - 10.3847/2041-8213/acd69f
M3 - Article
AN - SCOPUS:85164014496
SN - 2041-8205
VL - 949
JO - Astrophysical Journal Letters
JF - Astrophysical Journal Letters
IS - 2
M1 - L42
ER -