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Title: Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION

Abstract

We conducted a deep narrowband NB973 (FWHM = 200 A centered at 9755 A) survey of z = 7 Ly{alpha} emitters (LAEs) in the Subaru/XMM-Newton Deep Survey Field, using the fully depleted CCDs newly installed on the Subaru Telescope Suprime-Cam, which is twice more sensitive to z = 7 Ly{alpha} at {approx}1 {mu}m than the previous CCDs. Reaching the depth 0.5 mag deeper than our previous survey in the Subaru Deep Field that led to the discovery of a z = 6.96 LAE, we detected three probable z = 7 LAE candidates. Even if all the candidates are real, the Ly{alpha} luminosity function (LF) at z = 7 shows a significant deficit from the LF at z = 5.7 determined by previous surveys. The LAE number and Ly{alpha} luminosity densities at z = 7 are {approx}7.7%-54% and {approx}5.5%-39%, respectively, of those at z = 5.7, to the Ly{alpha} line luminosity limit of L(Ly{alpha}) {approx}> 9.2 x 10{sup 42} erg s{sup -1}. This could be due to evolution of the LAE population at these epochs as a recent galaxy evolution model predicts that the LAE modestly evolves from z = 5.7 to 7. However, even after correcting for this effect ofmore » galaxy evolution on the decrease in LAE number density, the z = 7 Ly{alpha} LF still shows a deficit from z = 5.7 LF. This might reflect the attenuation of Ly{alpha} emission by neutral hydrogen remaining at the epoch of reionization and suggests that reionization of the universe might not be complete yet at z = 7. If we attribute the density deficit to reionization, the intergalactic medium transmission for Ly{alpha} photons at z = 7 would be 0.4 {<=} T {sup IGM}{sub Ly{alpha} {<=}} 1, supporting the possible higher neutral fraction at the earlier epochs at z > 6 suggested by the previous surveys of z = 5.7-7 LAEs, z {approx} 6 quasars, and z > 6 gamma-ray bursts.« less

Authors:
;  [1]; ; ; ; ;  [2];  [3];  [4];  [5]; ;  [6]; ;  [7]
  1. Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa City, Chiba 77-8582 (Japan)
  2. National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)
  3. Department of Astronomy, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)
  4. Department of Astronomy, School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)
  5. Faculty of Education, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521 (Japan)
  6. Department of Physics, Saitama University, Shimo-Okubo 255, Sakura, Saitama 338-8570 (Japan)
  7. Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
Publication Date:
OSTI Identifier:
21464663
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 722; Journal Issue: 1; Other Information: DOI: 10.1088/0004-637X/722/1/803; Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COSMIC GAMMA BURSTS; COSMOLOGY; GALACTIC EVOLUTION; GALAXIES; HYDROGEN; LUMINOSITY; PHOTONS; QUASARS; TELESCOPES; UNIVERSE; BOSONS; COSMIC RADIATION; COSMIC RADIO SOURCES; ELEMENTARY PARTICLES; ELEMENTS; EVOLUTION; IONIZING RADIATIONS; MASSLESS PARTICLES; NONMETALS; OPTICAL PROPERTIES; PHYSICAL PROPERTIES; PRIMARY COSMIC RADIATION; RADIATIONS

Citation Formats

Ota, Kazuaki, Ouchi, Masami, Iye, Masanori, Kashikawa, Nobunari, Kobayashi, Masakazu A. R., Morokuma, Tomoki, Furusawa, Hisanori, Shimasaku, Kazuhiro, Totani, Tomonori, Nagashima, Masahiro, Harayama, Atsushi, Kodaka, Natsuki, Tajitsu, Akito, and Hattori, Takashi. Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION. United States: N. p., 2010. Web. doi:10.1088/0004-637X/722/1/803.
Ota, Kazuaki, Ouchi, Masami, Iye, Masanori, Kashikawa, Nobunari, Kobayashi, Masakazu A. R., Morokuma, Tomoki, Furusawa, Hisanori, Shimasaku, Kazuhiro, Totani, Tomonori, Nagashima, Masahiro, Harayama, Atsushi, Kodaka, Natsuki, Tajitsu, Akito, & Hattori, Takashi. Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION. United States. https://doi.org/10.1088/0004-637X/722/1/803
Ota, Kazuaki, Ouchi, Masami, Iye, Masanori, Kashikawa, Nobunari, Kobayashi, Masakazu A. R., Morokuma, Tomoki, Furusawa, Hisanori, Shimasaku, Kazuhiro, Totani, Tomonori, Nagashima, Masahiro, Harayama, Atsushi, Kodaka, Natsuki, Tajitsu, Akito, and Hattori, Takashi. 2010. "Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION". United States. https://doi.org/10.1088/0004-637X/722/1/803.
@article{osti_21464663,
title = {Ly{alpha} EMITTERS AT z = 7 IN THE SUBARU/XMM-NEWTON DEEP SURVEY FIELD: PHOTOMETRIC CANDIDATES AND LUMINOSITY FUNCTION},
author = {Ota, Kazuaki and Ouchi, Masami and Iye, Masanori and Kashikawa, Nobunari and Kobayashi, Masakazu A. R. and Morokuma, Tomoki and Furusawa, Hisanori and Shimasaku, Kazuhiro and Totani, Tomonori and Nagashima, Masahiro and Harayama, Atsushi and Kodaka, Natsuki and Tajitsu, Akito and Hattori, Takashi},
abstractNote = {We conducted a deep narrowband NB973 (FWHM = 200 A centered at 9755 A) survey of z = 7 Ly{alpha} emitters (LAEs) in the Subaru/XMM-Newton Deep Survey Field, using the fully depleted CCDs newly installed on the Subaru Telescope Suprime-Cam, which is twice more sensitive to z = 7 Ly{alpha} at {approx}1 {mu}m than the previous CCDs. Reaching the depth 0.5 mag deeper than our previous survey in the Subaru Deep Field that led to the discovery of a z = 6.96 LAE, we detected three probable z = 7 LAE candidates. Even if all the candidates are real, the Ly{alpha} luminosity function (LF) at z = 7 shows a significant deficit from the LF at z = 5.7 determined by previous surveys. The LAE number and Ly{alpha} luminosity densities at z = 7 are {approx}7.7%-54% and {approx}5.5%-39%, respectively, of those at z = 5.7, to the Ly{alpha} line luminosity limit of L(Ly{alpha}) {approx}> 9.2 x 10{sup 42} erg s{sup -1}. This could be due to evolution of the LAE population at these epochs as a recent galaxy evolution model predicts that the LAE modestly evolves from z = 5.7 to 7. However, even after correcting for this effect of galaxy evolution on the decrease in LAE number density, the z = 7 Ly{alpha} LF still shows a deficit from z = 5.7 LF. This might reflect the attenuation of Ly{alpha} emission by neutral hydrogen remaining at the epoch of reionization and suggests that reionization of the universe might not be complete yet at z = 7. If we attribute the density deficit to reionization, the intergalactic medium transmission for Ly{alpha} photons at z = 7 would be 0.4 {<=} T {sup IGM}{sub Ly{alpha} {<=}} 1, supporting the possible higher neutral fraction at the earlier epochs at z > 6 suggested by the previous surveys of z = 5.7-7 LAEs, z {approx} 6 quasars, and z > 6 gamma-ray bursts.},
doi = {10.1088/0004-637X/722/1/803},
url = {https://www.osti.gov/biblio/21464663}, journal = {Astrophysical Journal},
issn = {0004-637X},
number = 1,
volume = 722,
place = {United States},
year = {Sun Oct 10 00:00:00 EDT 2010},
month = {Sun Oct 10 00:00:00 EDT 2010}
}