Models for Dusty Lyα Emitters at High Redshift
Models for Dusty Lyα Emitters at High Redshift
复制标题
高红移的 Dusty Lyα 发射器模型
DOI：
10.1086/307276
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
M. Spaans
中科院分区：
文献类型：
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作者：
Z. Haiman;M. Spaans
将普拉斯-谢克特公式与处理星系内非均匀尘埃分布相结合，给出了尘埃高红移星系的Lyα辐射模型。结果发现，从星系逸出的Lyα辐射量强烈地依赖于恒星活动产生尘埃的时间，以及围绕电离OB星的H II区的环境不均匀性。与最近的观察结果以及之前未发现的结果都很好地吻合。虽然由于不确定因素，无法详细确定单个模型参数，但我们发现：(1)原始星系中的尘埃含量不超过5×108yr；(2)星系HⅡ区是不均匀的，具有秩序统一的云覆盖因子；(3)总的恒星形成效率至少为~5%。据预测，未来的观测可以探测到这些高达~8红移的Lyα星系。如果宇宙在ZR≲8时被重新电离，那么在zαZR处Ly≳发射体数量的相应减少可能被证明是一个有用的再电离时代的探测器。
Models are presented for the Lyα emission of dusty high-redshift galaxies by combining the Press-Schechter formalism with a treatment of the inhomogeneous dust distribution inside galaxies. It is found that the amount of Lyα radiation escaping from the galaxies strongly depends on the time over which the dust is produced through stellar activity and on the ambient inhomogeneity of the H II regions that surround the ionizing OB stars. Good agreement is found with recent observations, as well as with previous nondetections. Although a detailed determination of the individual model parameters is precluded by uncertainties, we find that (1) the dust content in primordial galaxies builds up in no more than ~5 × 108 yr, (2) the galactic H II regions are inhomogeneous with a cloud-covering factor of order unity, and (3) the overall star formation efficiency is at least ~5%. It is predicted that future observations can detect these Lyα galaxies up to redshifts of ~8. If the universe is reionized at zr ≲ 8, the corresponding decline in the number of Lyα emitters at z ≳ zr could prove to be a useful probe of the reionization epoch.