@article{24276c899baa4e6883ab4118d9901bb1,
title = "SILVERRUSH. IV. Lyα luminosity functions at z = 5.7 and 6.6 studied with ∼1300 Lyα emitters on the 14-21 deg2 sky",
abstract = "We present the Lyα luminosity functions (LFs) at z = 5.7 and 6.6 derived from a new large sample of 1266 Lyα emitters (LAEs) identified in total areas of 14 and 21 deg2, respectively, based on the early narrowband data of the Subaru/Hyper Suprime-Cam survey. Together with careful Monte Carlo simulations that account for the incompleteness of the LAE selection and the flux estimate systematics in the narrowband imaging, we have determined the Lyα LFs with unprecedentedly small statistical and systematic uncertainties in a wide Lyα luminosity range of 1042.8-43.8 erg s-1. We obtain best-fit Schechter parameters of L∗Lyα = 1.6-0.6+2.2 (1.7-0.7+0.3) × 1043 erg s-1, φ∗Lyα = 0.85-0.77+1.87 (0.47-0.44+1.44) × 10-4 Mpc-3, and α = -2.6-0.4+0.6 (-2.5-0.5+0.5) at z = 5.7 (6.6). We confirm that our best-estimate Lyα LFs are consistent with the majority of the previous studies, but find that our Lyα LFs do not agree with the high number densities of LAEs recently claimed by Matthee/Santos et al.'s studies that may overcorrect the incompleteness and the flux systematics. Our Lyα LFs at z = 5.7 and 6.6 show an indication that the faint-end slope is very steep (α - -2.5), although it is also possible that the bright-end LF results are enhanced by systematic effects such as the contribution from AGNs, blended merging galaxies, and/or large ionized bubbles around bright LAEs. Comparing our Lyα LF measurements with four independent reionization models, we estimate the neutral hydrogen fraction of the intergalactic medium to be xHI = 0.3 ± 0.2 at z = 6.6, which is consistent with the small Thomson scattering optical depth obtained by Planck 2016.",
keywords = "Cosmology, First stars-galaxies, Formation-galaxies, High-redshift-galaxies, Luminosity function, Mass function, Observations-dark ages, Reionization",
author = "Akira Konno and Masami Ouchi and Takatoshi Shibuya and Yoshiaki Ono and Kazuhiro Shimasaku and Yoshiaki Taniguchi and Tohru Nagao and Kobayashi, {Masakazu A.R.} and Masaru Kajisawa and Nobunari Kashikawa and Inoue, {Akio K.} and Masamune Oguri and Hisanori Furusawa and Tomotsugu Goto and Yuichi Harikane and Ryo Higuchi and Yutaka Komiyama and Haruka Kusakabe and Satoshi Miyazaki and Kimihiko Nakajima and Wang, {Shiang Yu}",
note = "Funding Information: The Pan-STARRS1 Surveys (PS1) have been made possible through contributions of 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, Queen{\textquoteright}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 under Grant No. AST-1238877, the University of Maryland, Eotvos Lorand University (ELTE), and the Los Alamos National Laboratory. Funding Information: The Hyper Suprime-Cam (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), the Japan Science and Technology Agency (JST), the Toray Science Foundation, NAOJ, Kavli IPMU, KEK, ASIAA, and Princeton University. Funding Information: A.K. acknowledges support from the Japan Society for the Promotion of Science (JSPS) through the JSPS Research Fellowship for Young Scientists. This work is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan, and KAKENHI (15H02064) Grant-in-Aid for Scientific Research (A) through the Japan Society for the Promotion of Science. N.K. acknowledges support from JSPS grant 15H03645. Publisher Copyright: {\textcopyright} The Author(s) 2017. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved.",
year = "2018",
month = jan,
day = "1",
doi = "10.1093/pasj/psx131",
language = "English",
volume = "70",
journal = "Publications of the Astronomical Society of Japan",
issn = "0004-6264",
publisher = "Astronomical Society of Japan",
number = "Special Issue 1",
}