Probing the Metal Enrichment of the Intergalactic Medium at z = 5–6 Using the Hubble Space Telescope
Probing the Metal Enrichment of the Intergalactic Medium at z = 5–6 Using the Hubble Space Telescope
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使用哈勃太空望远镜探测 z = 5–6 处星系间介质的金属富集
DOI：
10.3847/2041-8213/aa8fc6
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
B. Oppenheimer
中科院分区：
文献类型：
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作者：
Z. Cai;Xiaohui Fan;R. Davé;K. Finlator;B. Oppenheimer
我们测试的星系外流模型探测关联星系的4个强星系际C IV吸收在z = 5 - 6使用哈勃太空望远镜（HST）的高级相机的调查（ACS）斜坡窄带滤波器。四个强C iv吸收体位于z = 5.74、5.52、4.95和4.87处，柱密度范围为NC iv = 1013.8至1014.8 cm − 2。在z = 5.74时，我们检测到一个i-dropout Ly α发射体（LAE）候选体，其投射撞击参数为42物理kpc。这颗LAE候选星的Ly α基星星形成率（SFRLy α）为2 M yr − 1，UV基SFR为4 M yr − 1。虽然我们不能完全排除这个i-dropout发射体可能是一个[O ii]闯入者，但它的测量特性与z = 5.74的C iv动力星系一致。对于C IV吸收器在z = 4.95和z = 4.87，虽然我们检测到两个LAE候选人的影响参数为160和200千秒差距，这样的距离大于从模拟预测。因此，我们将其视为未检测。对于z = 5.52的系统，我们没有检测到LAE候选者，因此3 σ的上限为SFRLy α = 1.5 M yr − 1。总之，在这四种情况下，我们仅在z = 5.74处检测到一个合理的C iv源。结合一次探测和三次未探测的适度SFR，我们的HST观测强烈支持较小的星系（SFRLy α 12 M yr − 1）是星系际Civ吸收体的主要来源，并且这些小星系在z 15处的星系际介质的金属富集中起着重要作用。
We test the galactic outflow model by probing associated galaxies of four strong intergalactic C iv absorbers at z = 5–6 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) ramp narrowband filters. The four strong C iv absorbers reside at z = 5.74, 5.52, 4.95, and 4.87, with column densities ranging from NC iv = 1013.8 to 1014.8 cm−2. At z = 5.74, we detect an i-dropout Lyα emitter (LAE) candidate with a projected impact parameter of 42 physical kpc from the C iv absorber. This LAE candidate has a Lyα-based star formation rate (SFRLyα) of 2 M⊙ yr−1 and a UV-based SFR of 4 M⊙ yr−1. Although we cannot completely rule out that this i-dropout emitter may be an [O ii] interloper, its measured properties are consistent with the C iv powered galaxy at z = 5.74. For C iv absorbers at z = 4.95 and z = 4.87, although we detect two LAE candidates with impact parameters of 160 and 200 kpc, such distances are larger than that predicted from the simulations. Therefore, we treat them as nondetections. For the system at z = 5.52, we do not detect LAE candidates, placing a 3σ upper limit of SFRLyα ≈ 1.5 M⊙ yr−1. In summary, in these four cases, we only detect one plausible C iv source at z = 5.74. Combining the modest SFR of the one detection and the three nondetections, our HST observations strongly support that smaller galaxies (SFRLyα ≲ 2 M⊙ yr−1) are main sources of intergalactic C iv absorbers, and such small galaxies play a major role in the metal enrichment of the intergalactic medium at z ≳ 5.