COMPLETING THE CENSUS OF Ly alpha EMITTERS AT THE REIONIZATION EPOCH
COMPLETING THE CENSUS OF Ly alpha EMITTERS AT THE REIONIZATION EPOCH
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发表时间：
2011
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通讯作者：
N. Kashikawa;K. Shimasaku;Y. Matsuda;E. Egami;Linhua Jiang;T. Nagao;M. Ouchi;M. Malkan;T. Hattori
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作者：
N. Kashikawa;K. Shimasaku;Y. Matsuda;E. Egami;Linhua Jiang;T. Nagao;M. Ouchi;M. Malkan;T. Hattori
我们在z = 6处对Ly α发射体（LAEs）进行了扩展光谱确认。5和5 .斯巴鲁深野Subaru Deep Field现在，在z = 6时，光谱确认的LAE总数为45和54。5和5 . 7，分别和至少81%（70%）的我们的光度候选人在z = 6。5（5 . 7)已经被光谱鉴定为艾德的真实的LAE。我们对Ly α光度进行了仔细的测量，包括光度测量和光谱测量，以准确地确定Ly α和静止紫外光度函数（LF）。z = 6时Ly α LF的评估得到显著改进。5表示z = 5的明显亏损。7至少在光明的一端，甚至在暗淡的一端也可能下降，尽管仍存在一些不确定性。z = 6时的剩余UV LF。5和5 .至少在明亮的一端，与Ly α LF中看到的差异形成鲜明对比。这些结果意味着星系际介质的中性部分从z = 5开始增加。七比六。5. z = 6时的静息帧等效宽度（EW 0）分布。5似乎系统地小于z = 5。7，它显示了一个延伸的尾巴向更大的EW 0。静止-UV LF的亮端可以从观测到的Ly α LF和合理的EW 0 − UV光度关系中重现。对这个静止紫外LF进行积分，提供了LAEs对再电离所需光子预算的贡献的第一个测量。导出的UV LF表明LAEs对莱曼破裂星系中光子收支的贡献率在微弱的星等上显著增加。低光度LAEs可能主导电离光子收支，尽管这一推论强烈依赖于Ly α LF的不确定的暗端斜率。
We carried out extended spectroscopic confirmations of Ly α 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 α luminosity, both photometrically and spectroscopically, to accurately determine the Ly α and rest-UV luminosity functions (LFs). The substantially improved evaluation of the Ly α 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 α 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 (EW 0 ) distribution at z = 6 . 5 seems to be systematically smaller than z = 5 . 7, and it shows an extended tail toward larger EW 0 . The bright end of the rest-UV LF can be reproduced from the observed Ly α LF and a reasonable EW 0 − 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 α LF.