Broadband Selection, Spectroscopic Identification, and Physical Properties of a Population of Extreme Emission-line Galaxies at 3 < z < 3.7
Broadband Selection, Spectroscopic Identification, and Physical Properties of a Population of Extreme Emission-line Galaxies at 3 < z < 3.7
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DOI：
10.3847/1538-4357/abc174
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发表时间：
2020-10
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通讯作者：
M. Onodera;R. Shimakawa;Tomoko L. Suzuki;I. Tanaka;Y. Harikane;M. Hayashi;T. Kodama;Y. Koyama;K. Nakajima;T. Shibuya
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作者：
M. Onodera;R. Shimakawa;Tomoko L. Suzuki;I. Tanaka;Y. Harikane;M. Hayashi;T. Kodama;Y. Koyama;K. Nakajima;T. Shibuya
我们给出了在3 3处具有强[O III]发射的极端发射线星系(EELG)和在zα2处有H≃发射的极端发射线星系(ELLG)的选择、光谱鉴定和物理性质。这些光谱识别的eELG在z≃3.3时的平均比恒星形成率(SSFR)高于恒星形成主序，E(B−V)≲0.1mag的尘埃衰减率较低，≳3的[O III]/[O II]高。我们还发现，我们在z≃3.3时的eELG具有比标准值(ξIon)更高的氢电离光子产生效率(≃Ion)，这表明它们在电离周围星际介质方面是有效的。这些物理性质表明，它们是低金属丰度星系，比正常的SFG具有更高的电离参数和更硬的紫外光谱，这类似于莱曼连续谱(LYC)泄漏的星系。在我们的鳗鱼中，那些具有最大[O III]/[O II]和EW([O III])值的鳗鱼将是寻找LYC泄漏的最有希望的候选者。
We present the selection, spectroscopic identification, and physical properties of extreme emission-line galaxies (EELGs) at 3 3 with intense [O iii] emission and Hα emitters at z ≃ 2, respectively. These spectroscopically identified EELGs at z ≃ 3.3 show, on average, higher specific star formation rates (sSFRs) than the star-forming main sequence, low dust attenuation of E(B − V) ≲ 0.1 mag, and high [O iii]/[O ii]ratios of ≳3. We also find that our EELGs at z ≃ 3.3 have higher hydrogen-ionizing photon production efficiencies (ξion) than the canonical value (≃1025.2 erg−1 Hz), indicating that they are efficient in ionizing their surrounding interstellar medium. These physical properties suggest that they are low-metallicity galaxies with higher ionizing parameters and harder UV spectra than normal SFGs, which is similar to galaxies with Lyman continuum (LyC) leakage. Among our EELGs, those with the largest [O iii]/[O ii] and EW([O iii]) values would be the most promising candidates to search for LyC leakage.