Detection of nitrogen and oxygen in a galaxy at the end of reionization
Detection of nitrogen and oxygen in a galaxy at the end of reionization
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再电离结束时检测星系中的氮和氧
DOI：
10.1093/pasj/psac018
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发表时间：
2022
影响因子：
2.3
通讯作者：
Zavala Jorge
中科院分区：
文献类型：
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作者：
Tadaki Ken-ichi;Tsujita Akiyoshi;Tamura Yoichi;Kohno Kotaro;Hatsukade Bunyo;Iono Daisuke;Lee Minju M;Matsuda Yuichi;Michiyama Tomonari;Nagao Tohru;Nakanishi Kouichiro;Nishimura Yuri;Saito Toshiki;Umehata Hideki;Zavala Jorge
我们利用阿塔卡马大型毫米/亚毫米阵列 (ALMA) 对 [Nii] 205 μm、[Oiii] 88 μm 和强透镜亚毫米星系 (SMG) atz= 6.0、G09.83808 中的尘埃发射进行了观测。在分辨率图中，[Nii] 和 [Oiii] 线发射均在 >12σ 处检测到。透镜模型表明，灰尘连续发射的空间分布通过有效半径为0.64±0.02 kpc的光盘和ΣIR=(1.8±0.3)×1012L⊙kpc−2的高红外表面亮度来很好地表征。这一结果支持 G09.83808 是致密静止星系 atz∼4 的前身，其中大多数恒星预计是通过强烈而短暂的恒星形成爆发而形成的。 G09.83808 和其他透镜式 SMG 在 63 至 158μm 之间显示出 [Nii] 线与红外光度比随着连续通量密度比的增加而下降的趋势，如局部发光红外星系 (LIRG) 中所见。下降趋势可以通过电离参数增加的光电离模型来重现。此外，结合G09.83808中的[Nii]/[Oiii]光度比和远红外连续谱通量密度比，我们推断气相金属丰度已经为Z≈0.5–0.7Z⊙。 G09.83808 可能是最早在再电离结束时化学物质丰富的星系之一。
We present observations of [Nii] 205 μm, [Oiii] 88 μm, and dust emission in a strongly-lensed, submillimeter galaxy (SMG) atz= 6.0, G09.83808, with the Atacama Large Millimeter/submillimeter Array (ALMA). Both [Nii] and [Oiii] line emissions are detected at >12σ in the-resolution maps. Lens modeling indicates that the spatial distribution of the dust continuum emission is well characterized by a compact disk with an effective radius of 0.64 ± 0.02 kpc and a high infrared surface brightness of ΣIR= (1.8 ± 0.3) × 1012L⊙kpc−2. This result supports that G09.83808 is the progenitor of compact quiescent galaxies atz∼ 4, where the majority of its stars are expected to be formed through a strong and short burst of star formation. G09.83808 and other lensed SMGs show a decreasing trend in the [Nii] line to infrared luminosity ratio with increasing continuum flux density ratio between 63 and 158 μm, as seen in local luminous infrared galaxies (LIRGs). The decreasing trend can be reproduced by photoionization models with increasing ionization parameters. Furthermore, by combining the [Nii]/[Oiii] luminosity ratio with far-infrared continuum flux density ratio in G09.83808, we infer that the gas phase metallicity is alreadyZ≈ 0.5–0.7Z⊙. G09.83808 is likely one of the earliest galaxies that has been chemically enriched at the end of reionization.