The dominant origin of diffuse Ly α halos around LAEs explored by SED fitting and clustering analysis
The dominant origin of diffuse Ly α halos around LAEs explored by SED fitting and clustering analysis
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通过 SED 拟合和聚类分析探索 LAE 周围弥漫性 Ly α 晕的主要起源
DOI：
10.1093/pasj/psz029
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发表时间：
2019
影响因子：
2.3
通讯作者：
Peter L. Abstract
中科院分区：
文献类型：
--
作者：
Kusakabe;Haruka; Shimasaku;Kazuhiro; Momose;Rieko; Ouchi;Masami; Nakajima;Kimihiko; Hashimoto;Takuya; Harikane;Yuichi; Silverman;John D.; Capak;Peter L. Abstract
恒星形成星系周围弥漫Lyα晕（LAH）的物理起源仍然是一个有争议的问题。本文给出了10个子样本的LAH光度[L（Lyα）H]与母星系的恒星质量（M）、星星形成率、色余[E（B − V）]和暗物质晕质量（Mh）的关系。利用Momose等人的L（Ly α）与中心Lyα光度的叠加观测关系计算L（Ly α）Hu。(2016，MNRAS，457，2318），我们发现这与VLT/MUSE检测到的单个LAE的平均趋势一致。我们发现，尽管M_r和Mh较低，但LAE具有相对较高的L（Lyα）H，并且L（Lyα）H几乎不随M_r而变化，也可能随Mh而变化。这些结果与冷流（冷却辐射）方案和卫星-星系恒星形成方案是不一致的，因为前者预测的L（Lyα）较弱，而后者预测的L（Lyα）Hvs.Mvs.斜率较陡。我们认为LAH主要是由Lyα光子从主体逃逸到环星系介质中散射而产生的。这一论点得到了Hα发射体（HAE）的LAH观测的支持。当考虑LAH时，LAEs的Lyα逃逸分数比具有类似M介子或E（B − V）介子的HAE的Lyα逃逸分数高约10倍，这可能部分是由于较低的M固定M介子所隐含的较低的Higas质量，或来自中心部分的另一个Lyα源。
The physical origin of diffuse Lyα halos (LAHs) around star-forming galaxies is still a matter of debate. We present the dependence of LAH luminosity [L(Lyα)H] on the stellar mass (M⋆), star formation rate, color excess [E(B − V)⋆], and dark matter halo mass (Mh) of the parent galaxy for ∼900 Lyα emitters (LAEs) atz∼ 2 divided into ten subsamples. We calculateL(Lyα)Husing the stacked observational relation betweenL(Lyα)Hand central Lyα luminosity of Momose et al. (2016, MNRAS, 457, 2318), which we find agrees with the average trend of VLT/MUSE-detected individual LAEs. We find that our LAEs have relatively highL(Lyα)Hdespite lowM⋆andMh, and thatL(Lyα)Hremains almost unchanged withM⋆and perhaps withMh. These results are incompatible with the cold stream (cooling radiation) scenario and the satellite-galaxy star-formation scenario, because the former predicts fainterL(Lyα)Hand both predict steeperL(Lyα)Hvs.M⋆slopes. We argue that LAHs are mainly caused by Lyα photons escaping from the main body and then scattering in the circum-galactic medium. This argument is supported by LAH observations of Hα emitters (HAEs). When LAHs are taken into account, the Lyα escape fractions of our LAEs are about ten times higher than those of HAEs with similarM⋆orE(B − V)⋆, which may partly arise from lower Higas masses implied from lowerMhat fixedM⋆, or from another Lyα source in the central part.