FIRST SPECTROSCOPIC EVIDENCE FOR HIGH IONIZATION STATE AND LOW OXYGEN ABUNDANCE IN Lyα EMITTERS,
FIRST SPECTROSCOPIC EVIDENCE FOR HIGH IONIZATION STATE AND LOW OXYGEN ABUNDANCE IN Lyα EMITTERS,
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DOI：
10.1088/0004-637x/769/1/3
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
K. Nakajima;M. Ouchi;K. Shimasaku;T. Hashimoto;Y. Ono;Janice C. Lee
中科院分区：
文献类型：
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作者：
K. Nakajima;M. Ouchi;K. Shimasaku;T. Hashimoto;Y. Ono;Janice C. Lee
我们介绍了在斯巴鲁窄带调查中发现的z = 2.2的Lyα发射体（LAEs）的Keck/NIRSPEC和麦哲伦/MMIRS跟踪光谱结果。我们成功地探测到了7个LAEs的Hα辐射，并对6个没有活跃星系核活动的LAEs进行了详细的分析，其中CDFS-3865和COSMOS-30679有[O ii]和[O iii]谱线检测。它们是第一批在高z下检测到的[O ii] LAEs，它们的[O iii]/[O ii]比值和r23指数首次提供了LAEs的电离参数和氧丰度的同时测定。CDFS-3865具有非常高的电离参数（cm s−1）和较低的氧丰度（），而其他高z星系（如Lyman break星系（LBGs））具有中等的电离值。COSMOS-30679还具有较高的电离参数（cm s−1）和较低的氧丰度（）。两种lae似乎都低于z ~ 2 LBGs的质量-金属丰度关系。同样，低金属丰度为12 + log (O/H) 6。
We present results from Keck/NIRSPEC and Magellan/MMIRS follow-up spectroscopy of Lyα emitters (LAEs) at z = 2.2 identified in our Subaru narrowband survey. We successfully detect Hα emission from seven LAEs, and perform a detailed analysis of six LAEs free from active galactic nucleus activity, two out of which, CDFS-3865 and COSMOS-30679, have [O ii] and [O iii] line detections. They are the first [O ii]-detected LAEs at high-z, and their [O iii]/[O ii] ratios and R23-indices provide the first simultaneous determinations of ionization parameter and oxygen abundance for LAEs. CDFS-3865 has a very high ionization parameter ( cm s−1) and a low oxygen abundance () in contrast with moderate values of other high-z galaxies such as Lyman break galaxies (LBGs). COSMOS-30679 also possesses a relatively high ionization parameter ( cm s−1) and a low oxygen abundance (). Both LAEs appear to fall below the mass–metallicity relation of z ∼ 2 LBGs. Similarly, a low metallicity of 12 + log (O/H) 6.