STATISTICS OF 207 Lyα EMITTERS AT A REDSHIFT NEAR 7: CONSTRAINTS ON REIONIZATION AND GALAXY FORMATION MODELS

Content Provider	Scilit
Author	Ouchi, Masami Shimasaku, Kazuhiro Furusawa, Hisanori Saito, Tomoki Yoshida, Makiko Akiyama, Masayuki Ono, Yoshiaki Yamada, Toru Ota, Kazuaki Kashikawa, Nobunari Iye, Masanori Kodama, Tadayuki Okamura, Sadanori Simpson, Chris Yoshida, Michitoshi
Copyright Year	2010
Description	Journal: The Astrophysical Journal We present the Lyα luminosity function (LF), clustering measurements, and Lyα line profiles based on the largest sample to date of 207 Lyα emitters (LAEs) at z = 6.6 on the 1 $deg^{2}$ sky of Subaru/XMM-Newton Deep Survey field. Our z = 6.6 Lyα LF including cosmic variance estimates yields the best-fit Schechter parameters of * = $8.5^{+3.0} _{–2.2}$ × $10^{–4}$ $Mpc^{–3}$ and $L*_{Lyα}$ = $4.4^{+0.6} _{–0.6}$ × $10^{42}$ erg $s^{–1}$ with a fixed α = –1.5, and indicates a decrease from z = 5.7 at the 90% confidence level. However, this decrease is not large, only 30% in Lyα 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$ _{0}$= 2-5 h$ ^{–1} _{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 $10^{10}-10^{11}$ M$ _{☉}$, and a duty cycle of LAE population is roughly ~1%, albeit with large uncertainties. The average of our high-quality Keck/DEIMOS spectra shows an FWHM velocity width of 251 ± 16 km $s^{–1}$. We find no large evolution of the Lyα line profile from z = 5.7 to 6.6, and no anti-correlation between Lyα 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) Lyα 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 7.
Related Links	http://iopscience.iop.org/article/10.1088/0004-637X/723/1/869/pdf
Ending Page	894
Page Count	26
Starting Page	869
ISSN	0004637X
DOI	10.1088/0004-637x/723/1/869
Journal	The Astrophysical Journal
Issue Number	1
Volume Number	723
Language	English
Publisher	IOP Publishing
Publisher Date	2010-10-15
Access Restriction	Open
Subject Keyword	Journal: The Astrophysical Journal Astronomy and Astrophysics Subject Headings: Galaxies: Formation — Galaxies: High-redshift — Galaxies: Luminosity Function — Cosmology: Observations Luminosity Function
Content Type	Text
Resource Type	Article
Subject	Astronomy and Astrophysics Space and Planetary Science