Q1549-C25: A CLEAN SOURCE OF LYMAN-CONTINUUM EMISSION AT z = 3.15
Q1549-C25: A CLEAN SOURCE OF LYMAN-CONTINUUM EMISSION AT z = 3.15
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Q1549-C25：z = 3.15 时莱曼连续发射的清洁源
DOI：
10.3847/2041-8205/826/2/l24
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
G. Rudie
中科院分区：
文献类型：
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作者：
A. Shapley;C. Steidel;A. Strom;Milan Bogosavljević;N. Reddy;B. Siana;R. Mostardi;G. Rudie
我们给出了Q1549-C25的观测结果。Q1549-C25是一个∼L*恒星形成星系，在z=3.15时，在深Keck/LRIS光谱中显著地探测到了莱曼连续辐射。在Q1549-C25的高信噪比光谱中，我们没有发现接近视线的低红移入侵者的污染证据。此外，在V606、J125和H160哈勃太空望远镜(HST)成像中，Q1549-C25的形态表明，该对象由1“内的单个孤立组件组成。结合这些数据，这些数据表明Q1549-C25是对LYC辐射的干净光谱探测，只是到目前为止在z∼3发现的第二个这样的天体。我们模拟了Q1549-C25的光谱能量分布，发现了可以忽略不计的尘埃消光的证据，∼1 Gyr的年龄(假设连续恒星形成)，以及M*=7.9x109M⊙的恒星质量。虽然不可能从单个天体得出对LYC发射的绝对逃逸分数FESC(LYC)的强烈约束，但我们使用星系间和星系圈吸收的模拟来推断FESC(LYC)≥0.51，置信度为95%。为了收集更大样本的天体，如Q1549-C25，并获得对z∼3及以上的平均FESC(LYC)的可靠约束，需要将深度Keck/LRIS光谱学和哈勃太空望远镜成像相结合。
We present observations of Q1549-C25, an ∼ L * star-forming galaxy at z = 3.15 for which Lyman-continuum (LyC) radiation is significantly detected in deep Keck/LRIS spectroscopy. We find no evidence of contamination from a lower-redshift interloper close to the line of sight in the high signal-to-noise spectrum of Q1549-C25. Furthermore, the morphology of Q1549-C25 in V606, J125, and H160 Hubble Space Telescope (HST) imaging reveals that the object consists of a single, isolated component within 1″. In combination, these data indicate Q1549-C25 as a clean spectroscopic detection of LyC radiation, only the second such object discovered to date at z ∼ 3. We model the spectral energy distribution of Q1549-C25, finding evidence of negligible dust extinction, an age (assuming continuous star formation) of ∼1 Gyr, and a stellar mass of M * = 7.9 × 10 9 M ⊙ . Although it is not possible to derive strong constraints on the absolute escape fraction of LyC emission, fesc(LyC), from a single object, we use simulations of intergalactic and circumgalactic absorption to infer f esc ( LyC ) ≥ 0.51 at 95% confidence. The combination of deep Keck/LRIS spectroscopy and Hubble Space Telescope imaging is required to assemble a larger sample of objects like Q1549-C25, and obtain robust constraints on the average fesc(LyC) at z ∼ 3 and beyond.