A New Constraint on Reionization from the Evolution of the Lyα Luminosity Function at z ∼ 6-7 Probed by a Deep Census of z = 7.0 Lyα Emitter Candidates to 0.3L

Kazuaki Ota*, Masanori Iye, Nobunari Kashikawa, Akira Konno, Fumiaki Nakata, Tomonori Totani, Masakazu A.R. Kobayashi, Yoshinobu Fudamoto, Akifumi Seko, Jun Toshikawa, Akie Ichikawa, Takatoshi Shibuya, Masafusa Onoue

*この研究の対応する著者

研究成果: Article査読

38 被引用数 (Scopus)

抄録

We detect 20 z = 7.0 Lyα emitter (LAE) candidates to L(Lyα) ∼ 2 × 1042 erg s-1 or 0.3 and in a volume of 6.1 × 105 Mpc3 in the Subaru Deep Field and the Subaru/XMM-Newton Deep Survey field by 82 hr and 37 hr of Subaru Suprime-Cam narrowband NB973 and reddest optical y-band imaging. We compare their Lyα and UV luminosity functions (LFs) and densities and Lyα equivalent widths (EWs) to those of z = 5.7, 6.6, and 7.3 LAEs from previous Suprime-Cam surveys. The Lyα LF (density) rapidly declines by a factor of ×1.5 (1.9) in L(Lyα) at z = 5.7-6.6 (160 Myr), ×1.5 (1.6) at z = 6.6-7.0 (60 Myr) at the faint end, and ×2.0 (3.8) at z = 7.0-7.3 (40 Myr). Also, in addition to the systematic decrease in EW at z = 5.7-6.6 previously found, two-thirds of the z = 7.0 LAEs detected in the UV continuum exhibit lower EWs than the z = 6.6 ones. Moreover, while the UV LF and density do not evolve at z = 5.7-6.6, they modestly decline at z = 6.6-7.0, implying galaxy evolution contributing to the decline of the Lyα LF. Comparison of the z = 7.0 Lyα LF to the one predicted by an LAE evolution model further reveals that galaxy evolution alone cannot explain all of the decline of the Lyα LF. If we attribute the discrepancy to Lyα attenuation by neutral hydrogen, the intergalactic medium transmission of Lyα photons at z = 7.0 would be . It is lower (higher) than the at z = 6.6 (7.3) derived by previous studies, suggesting rapid increase in neutral fraction at z > 6.

本文言語English
論文番号85
ジャーナルAstrophysical Journal
844
1
DOI
出版ステータスPublished - 2017 7 20
外部発表はい

ASJC Scopus subject areas

  • 天文学と天体物理学
  • 宇宙惑星科学

フィンガープリント

「A New Constraint on Reionization from the Evolution of the Lyα Luminosity Function at z ∼ 6-7 Probed by a Deep Census of z = 7.0 Lyα Emitter Candidates to 0.3L <sup>∗</sup>」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

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