STATISTICS OF 207 Ly{alpha} EMITTERS AT A REDSHIFT NEAR 7: CONSTRAINTS ON REIONIZATION AND GALAXY FORMATION MODELS

Journal Article · Mon Nov 01 04:00:00 EDT 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/1/869· OSTI ID:21467152

Ouchi, Masami; Ota, Kazuaki ^[1]; Shimasaku, Kazuhiro; Yoshida, Makiko; Ono, Yoshiaki; Okamura, Sadanori ^[2]; Furusawa, Hisanori; Kashikawa, Nobunari; Iye, Masanori; Kodama, Tadayuki ^[3]; Saito, Tomoki ^[4]; Akiyama, Masayuki; Yamada, Toru ^[5]; Simpson, Chris ^[6]; Yoshida, Michitoshi ^[7]

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1. Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan)
2. Department of Astronomy, School of Science, University of Tokyo, Tokyo 113-0033 (Japan)
3. National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)
4. Institute for the Physics and Mathematics of the Universe (IPMU), University of Tokyo, Kashiwa 277-8568 (Japan)
5. Astronomical Institute, Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai 980-8578 (Japan)
6. Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom)
7. Okayama Astrophysical Observatory, National Astronomical Observatory, Kamogata, Okayama 719-0232 (Japan)

We present the Ly{alpha} luminosity function (LF), clustering measurements, and Ly{alpha} line profiles based on the largest sample to date of 207 Ly{alpha} emitters (LAEs) at z = 6.6 on the 1 deg{sup 2} sky of Subaru/XMM-Newton Deep Survey field. Our z = 6.6 Ly{alpha} LF including cosmic variance estimates yields the best-fit Schechter parameters of {phi}* = 8.5{sup +3.0}{sub -2.2} x 10{sup -4} Mpc{sup -3} and L*{sub Ly{alpha}} = 4.4{sup +0.6}{sub -0.6} x 10{sup 42} erg s{sup -1} with a fixed {alpha} = -1.5, and indicates a decrease from z = 5.7 at the {approx}>90% confidence level. However, this decrease is not large, only {approx_equal}30% in Ly{alpha} luminosity, which is too small to have been identified in the previous studies. A clustering signal of z = 6.6 LAEs is detected for the first time. We obtain the correlation length of r{sub 0}= 2-5 h {sup -1}{sub 100} Mpc and a bias of b= 3-6, and find no significant boost of clustering amplitude by reionization at z = 6.6. The average hosting dark halo mass inferred from clustering is 10{sup 10}-10{sup 11} M{sub sun}, and a duty cycle of LAE population is roughly {approx}1%, albeit with large uncertainties. The average of our high-quality Keck/DEIMOS spectra shows an FWHM velocity width of 251 {+-} 16 km s{sup -1}. We find no large evolution of the Ly{alpha} line profile from z = 5.7 to 6.6, and no anti-correlation between Ly{alpha} luminosity and line width at z = 6.6. The combination of various reionization models and our observational results about the LF, clustering, and line profile indicates that there would exist a small decrease of the intergalactic medium's (IGM's) Ly{alpha} transmission owing to reionization, but that the hydrogen IGM is not highly neutral at z = 6.6. Our neutral-hydrogen fraction constraint implies that the major reionization process took place at z {approx}> 7.

• OSTI ID: 21467152
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 723; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
COSMOLOGY
EVOLUTION
GALACTIC EVOLUTION
GALAXIES
HYDROGEN 5
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
LINE WIDTHS
LUMINOSITY
NUCLEI
ODD-EVEN NUCLEI
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
RED SHIFT
STARS