TY - JOUR
T1 - CHORUS. IV. Mapping the Spatially Inhomogeneous Cosmic Reionization with Subaru HSC
AU - Yoshioka, Takehiro
AU - Kashikawa, Nobunari
AU - Inoue, Akio K.
AU - Yamanaka, Satoshi
AU - Shimasaku, Kazuhiro
AU - Harikane, Yuichi
AU - Shibuya, Takatoshi
AU - Momose, Rieko
AU - Ito, Kei
AU - Liang, Yongming
AU - Ishimoto, Rikako
AU - Takeda, Yoshihiro
AU - Ouchi, Masami
AU - Lee, Chien Hsiu
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 of 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:
T.Y. is supported by the International Graduate Program for Excellence in Earth-Space Science (IGPEES). N.K. is supported by JSPS grant 21H04490. A.K.I. is supported by JSPS grant 21H04489. K.I. acknowledges support from JSPS grant 20J12461. R.M. acknowledges a Japan Society for the Promotion of Science (JSPS) Fellowship at Japan and JSPS KAKENHI grant No. JP18J40088. R.I. acknowledges support from JST SPRING, Grant Number JPMJSP2108.
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 Queens 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, Eötvos Loránd University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation.
Publisher Copyright:
© 2022. The Author(s). Published by the American Astronomical Society.
PY - 2022/3/1
Y1 - 2022/3/1
N2 - Spatial inhomogeneity is one of the important features for understanding the reionization process; however, it has not yet been fully quantified. To map this inhomogeneous distribution, we simultaneously detect Lyα emitters (LAEs) and Lyman-break galaxies (LBGs) at z ∼6.6 from the Subaru/Hyper Suprime-Cam large-area (∼1.5 deg2 = 34,000 cMpc2) deep survey. We estimate the neutral fraction, x HI, from the observed number density ratio of LAEs to LBGs, n(LAE)/n(LBG), using numerical radiative transfer simulations, in which model galaxies are selected to satisfy the observed selection function. While the average x HI within the field of view is found to be x HI < 0.4, which is consistent with previous studies, the variation of n(LAE)/n(LBG) within the field of view for every 140 pMpc2 area is found to be as large as a factor of 3. This may suggest a spatially inhomogeneous topology of reionization, but it also leaves open the possibility that the variation is based on the inherent large-scale structure of the galaxy distribution. Based on the simulations, it may be difficult to distinguish between the two from the current survey. We also find that LAEs in the high-LAE-density region are more numerous at high EW0, supporting the fact that the observed n(LAE)/n(LBG) is more or less driven by the neutral fraction, though the statistical significance is not high.
AB - Spatial inhomogeneity is one of the important features for understanding the reionization process; however, it has not yet been fully quantified. To map this inhomogeneous distribution, we simultaneously detect Lyα emitters (LAEs) and Lyman-break galaxies (LBGs) at z ∼6.6 from the Subaru/Hyper Suprime-Cam large-area (∼1.5 deg2 = 34,000 cMpc2) deep survey. We estimate the neutral fraction, x HI, from the observed number density ratio of LAEs to LBGs, n(LAE)/n(LBG), using numerical radiative transfer simulations, in which model galaxies are selected to satisfy the observed selection function. While the average x HI within the field of view is found to be x HI < 0.4, which is consistent with previous studies, the variation of n(LAE)/n(LBG) within the field of view for every 140 pMpc2 area is found to be as large as a factor of 3. This may suggest a spatially inhomogeneous topology of reionization, but it also leaves open the possibility that the variation is based on the inherent large-scale structure of the galaxy distribution. Based on the simulations, it may be difficult to distinguish between the two from the current survey. We also find that LAEs in the high-LAE-density region are more numerous at high EW0, supporting the fact that the observed n(LAE)/n(LBG) is more or less driven by the neutral fraction, though the statistical significance is not high.
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U2 - 10.3847/1538-4357/ac4b5d
DO - 10.3847/1538-4357/ac4b5d
M3 - Article
AN - SCOPUS:85126631474
SN - 0004-637X
VL - 927
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 1
M1 - 32
ER -