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arXiv 2209.03374astro-ph.GA
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通过 JWST/NIRCam 无缝光谱首次获得 z > 6 的 Hα+[O III] λ5007 发射线星系样本:物理性质与谱线光度函数

First Sample of H$α$+[O III] $λ$5007 Line Emitters at $z > 6$ Through JWST/NIRCam Slitless Spectroscopy: Physical Properties and Line Luminosity Functions

Fengwu Sun, Eiichi Egami, Nor Pirzkal, Marcia Rieke, Stefi Baum, Martha Boyer, Kristan Boyett, Andrew J. Bunker, Alex J. Cameron, Mirko Curti, Daniel J. Eisenst… 展开作者

Fengwu Sun, Eiichi Egami, Nor Pirzkal, Marcia Rieke, Stefi Baum, Martha Boyer, Kristan Boyett, Andrew J. Bunker, Alex J. Cameron, Mirko Curti, Daniel J. Eisenstein, Mario Gennaro, Thomas P. Greene, Daniel Jaffe, Doug Kelly, Anton M. Koekemoer, Nimisha Kumari, Roberto Maiolino, Michael Maseda, Michele Perna, Armin Rest, Brant E. Robertson, Everett Schlawin, Renske Smit, John Stansberry, Ben Sunnquist, Sandro Tacchella, Christina C. Williams, Christopher N. A. Willmer

AI总结:

本文利用 JWST/NIRCam 无缝光谱在 z>6 发现四个 Hα+[O III] 发射线星系,揭示其亚太阳金属丰度、高电离光子产生效率,并给出谱线光度函数演化及 Lyα 逃逸分数约束。

摘要:

我们给出了一个由四个发射线星系组成的样本,它们位于 z=6.11–6.35,是利用 JWST/NIRCam 宽场无缝光谱(WFSS)模式的试运行数据偶然发现的。其中一个(z=6.11)此前已有报道,其余均为新发现。这些源通过 [O III] λ5007 和 Hα 谱线的可靠探测被选出,部分源中还初步探测到其他较弱的谱线(例如 [O II] λ3727、[O III] λ4959)。在 [O III]/Hβ–[N II]/Hα 的 Baldwin-Phillips-Terlevich 图中,这些星系占据与 z∼2 恒星形成星系相同的参数空间,表明它们已迅速增丰至亚太阳金属丰度(约 0.4 Z⊙),与红移低得多、恒星质量相当的星系类似。强 Hα 谱线的探测表明早期宇宙中星系内部的电离光子产生效率更高。我们发现 [O III] λ5007 谱线光度函数(LF)从 z=3 到 6 变亮,而 Hα 谱线光度函数从 z=2 到 6 几乎没有或完全没有红移演化。在某些宇宙学模拟中,这两个光度函数在 z∼6 处均被低估了约 10 倍。这进一步表明在 z∼6 处全局 Lyα 光子逃逸分数为 7–10%,略低于此前通过比较紫外导出的恒星形成率密度与 Lyα 光度密度所得的估计值。我们的样本恢复了巡天体积中 z=6.0–6.6、恒星质量大于 5×10^8 M⊙ 星系的 66^{+128}_{-44}%,表明在再电离时期强 Hα 和 [O III] 发射线星系普遍存在,这些将在 JWST 时代被进一步揭示。

英文摘要:

We present a sample of four emission-line galaxies at $z=6.11-6.35$ that were serendipitously discovered using the commissioning data for the JWST/NIRCam wide-field slitless spectroscopy (WFSS) mode. One of them (at $z=6.11$) has been reported previously while the others are new discoveries. These sources are selected by the secure detections of both [O III] $λ$5007 and H$α$ lines with other fainter lines tentatively detected in some cases (e.g., [O II] $λ$3727, [O III] $λ$4959). In the [O III]/H$β$ - [N II]/H$α$ Baldwin-Phillips-Terlevich diagram, these galaxies occupy the same parameter space as that of $z\sim2$ star-forming galaxies, indicating that they have been enriched rapidly to sub-solar metallicities ($\sim$0.4 $Z_{\odot}$), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong H$α$ lines suggests a higher ionizing photon production efficiency within galaxies in the early Universe. We find brightening of the [O III] $λ$5007 line luminosity function (LF) from $z=3$ to 6, and weak or no redshift evolution of the H$α$ line LF from $z=2$ to 6. Both LFs are under-predicted at $z\sim6$ by a factor of $\sim$10 in certain cosmological simulations. This further indicates a global Ly$α$ photon escape fraction of 7-10% at $z\sim6$, slightly lower than previous estimates through the comparison of the UV-derived star-formation rate density and Ly$α$ luminosity density. Our sample recovers $66^{+128}_{-44}$% of $z=6.0-6.6$ galaxies in the survey volume with stellar masses greater than $5\times10^8$ $M_{\odot}$, suggesting the ubiquity of strong H$α$ and [O III] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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