COMPLETING THE CENSUS OF Lyα EMITTERS AT THE REIONIZATION EPOCH

被引：218

作者：

Kashikawa, Nobunari ^{[1
,2
]}

Shimasaku, Kazuhiro ^{[3
,4
]}

Matsuda, Yuichi ^{[5
]}

Egami, Eiichi ^{[6
]}

Jiang, Linhua ^{[6
]}

Nagao, Tohru ^{[7
]}

Ouchi, Masami ^{[8
]}

Malkan, Matthew A. ^{[9
]}

Hattori, Takashi ^{[10
]}

Ota, Kazuaki ^{[8
]}

Taniguchi, Yoshiaki ^{[7
]}

Okamura, Sadanori ^{[3
,4
]}

Ly, Chun ^{[11
]}

Iye, Masanori ^{[1
,2
]}

Furusawa, Hisanori ^{[12
]}

Shioya, Yasuhiro ^{[7
]}

Shibuya, Takatoshi ^{[2
]}

Ishizaki, Yoshifumi ^{[2
]}

Toshikawa, Jun ^{[2
]}

机构：

[1] Natl Astron Observ, Opt & Infrared Astron Div, Mitaka, Tokyo 1818588, Japan

[2] Grad Univ Adv Studies, Dept Astron, Sch Sci, Mitaka, Tokyo 1818588, Japan

[3] Univ Tokyo, Dept Astron, Tokyo 1130033, Japan

[4] Univ Tokyo, Res Ctr Early Universe, Tokyo 1130033, Japan

[5] Univ Durham, Dept Phys, Durham DH1 3LE, England

[6] Univ Arizona, Steward Observ, Tucson, AZ 85721 USA

[7] Ehime Univ, Res Ctr Space & Cosm Evolut, Bunkyo Cho, Matsuyama 7908577, Japan

[8] Univ Tokyo, Inst Cosm Ray Res, Kashiwa, Chiba 778582, Japan

[9] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA

[10] Natl Inst Nat Sci, Natl Astron Observ Japan, Subaru Telescope, Hilo, HI 96720 USA

[11] Space Telescope Sci Inst, Baltimore, MD 21218 USA

[12] Natl Astron Observ, Astron Data Ctr, Mitaka, Tokyo 1818588, Japan

来源：

ASTROPHYSICAL JOURNAL | 2011年 / 734卷 / 02期

基金：

日本学术振兴会;

关键词：

cosmology: observations; early universe; galaxies: formation; galaxies: high-redshift; LYMAN-BREAK GALAXIES; SUBARU DEEP FIELD; REST-FRAME ULTRAVIOLET; SPACE-TELESCOPE SEARCH; STAR-FORMATION HISTORY; LARGE EQUIVALENT WIDTH; HIGH-REDSHIFT GALAXIES; SIMILAR-TO; LUMINOSITY FUNCTIONS; COSMIC REIONIZATION;

D O I：

10.1088/0004-637X/734/2/119

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We carried out extended spectroscopic confirmations of Ly alpha emitters (LAEs) at z = 6.5 and 5.7 in the Subaru Deep Field. Now, the total number of spectroscopically confirmed LAEs is 45 and 54 at z = 6.5 and 5.7, respectively, and at least 81% (70%) of our photometric candidates at z = 6.5 (5.7) have been spectroscopically identified as real LAEs. We made careful measurements of the Ly alpha luminosity, both photometrically and spectroscopically, to accurately determine the Ly alpha and rest-UV luminosity functions (LFs). The substantially improved evaluation of the Ly alpha LF at z = 6.5 shows an apparent deficit from z = 5.7 at least at the bright end, and a possible decline even at the faint end, though small uncertainties remain. The rest-UV LFs at z = 6.5 and 5.7 are in good agreement, at least at the bright end, in clear contrast to the differences seen in the Ly alpha LF. These results imply an increase in the neutral fraction of the intergalactic medium from z = 5.7 to 6.5. The rest-frame equivalent width (EW0) distribution at z = 6.5 seems to be systematically smaller than z = 5.7, and it shows an extended tail toward larger EW0. The bright end of the rest-UV LF can be reproduced from the observed Ly alpha LF and a reasonable EW0-UV luminosity relation. Integrating this rest-UV LF provides the first measurement of the contribution of LAEs to the photon budget required for reionization. The derived UV LF suggests that the fractional contribution of LAEs to the photon budget among Lyman break galaxies significantly increases toward faint magnitudes. Low-luminosity LAEs could dominate the ionizing photon budget, though this inference depends strongly on the uncertain faint-end slope of the Ly alpha LF.

引用

页数：19

共 95 条

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