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arXiv 1706.09428astro-ph.GA
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一个位于$z=5.4$并具有强Ly $α$发射的明亮透镜星系

A bright lensed galaxy at $z=5.4$ with strong Ly$α$ emission

Ian D. McGreer, Benjamin Clément, Ramesh Mainali, Daniel P. Stark, Max Gronke, Mark Dijkstra, Xiaohui Fan, Fuyan Bian, Brenda Frye, Linhua Jiang, Jean-Paul Knei… 展开作者

Ian D. McGreer, Benjamin Clément, Ramesh Mainali, Daniel P. Stark, Max Gronke, Mark Dijkstra, Xiaohui Fan, Fuyan Bian, Brenda Frye, Linhua Jiang, Jean-Paul Kneib, Marceau Limousin, Gregory Walth

摘要:

我们提出了一个异常明亮的,透镜星系在$z=5.424$ CFHTLS成像调查中发现的详细研究。J141446.82+544631.9的观测通量为$i_{\rm AB}=23.0$,是$z>5$已知最亮的星系之一。其特征在于强的Ly $α$发射,在$>10^{-16}~{\rm erg}~{\rm s}^{-1}~{\rm cm}^{-2}~{\rm Å}^{-1}$的(观察到的)通量密度中达到峰值。来自LBT的深光谱对NV和CIV发射施加了很强的限制,不利于AGN源的发射。然而,探测到NIV]~ $λ$ 1486的发射线表明,这是一个硬电离连续谱,可能来自炽热的大质量恒星。来自HST的解析图像将星系从前景闯入者中分离出来;这些观测包括Ly $α$发射的窄带图像,它在$\sim$几~kpc尺度上勉强分辨,EW $_0~\sim$ 260 nm。Ly的$α$发射范围超过~2000~ ${\rm km}~{\rm s}^{-1}$,与膨胀壳模型基本一致。SED拟合,包括斯皮策/IRAC测光表明一个复杂的恒星形成历史,包括最近的爆发和进化的人口。J1414+5446距离CFHTLS中一个已知透镜群的中心30”;结合前景贡献,这导致在$5 \leq μ\leq 25$范围内对透镜放大率的高度不确定估计。由于其不寻常的亮度,J1414+5446提供了独特的机会,可以详细研究再电离时期附近的单个星系,并预览即将到来的广域调查将产生数百个类似的物体。

英文摘要:

We present a detailed study of a unusually bright, lensed galaxy at $z=5.424$ discovered within the CFHTLS imaging survey. With an observed flux of $i_{\rm AB}=23.0$, J141446.82+544631.9 is one of the brightest galaxies known at $z>5$. It is characterized by strong Ly$α$ emission, reaching a peak in (observed) flux density of $>10^{-16}~{\rm erg}~{\rm s}^{-1}~{\rm cm}^{-2}~{\rm Å}^{-1}$. A deep optical spectrum from the LBT places strong constraints on NV and CIV emission, disfavouring an AGN source for the emission. However, a detection of the NIV]~$λ$1486 emission line indicates a hard ionizing continuum, possibly from hot, massive stars. Resolved imaging from HST deblends the galaxy from a foreground interloper; these observations include narrowband imaging of the Ly$α$ emission, which is marginally resolved on $\sim$few~kpc scales and has EW$_0~\sim$ 260Å. The Ly$α$ emission extends over ~2000~${\rm km}~{\rm s}^{-1}$ and is broadly consistent with expanding shell models. SED fitting that includes Spitzer/IRAC photometry suggests a complex star formation history that include both a recent burst and an evolved population. J1414+5446 lies 30" from the centre of a known lensing cluster in the CFHTLS; combined with the foreground contribution this leads to a highly uncertain estimate for the lensing magnification in the range $5 \leq μ\leq 25$. Because of its unusual brightness J1414+5446 affords unique opportunities for detailed study of an individual galaxy near the epoch of reionization and a preview of what can be expected from upcoming wide-area surveys that will yield hundreds of similar objects.

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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