The expected abundance of Lyman-α emitting primeval galaxies I. General model predictions
The expected abundance of Lyman-α emitting primeval galaxies I. General model predictions
复制标题
莱曼-α 发射原始星系的预期丰度 I. 一般模型预测
DOI：
10.1051/0004-6361:20035863
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发表时间：
2005
影响因子：
6.5
通讯作者：
K. Meisenheimer
中科院分区：
文献类型：
--
作者：
E. Thommes;E. Thommes;K. Meisenheimer
我们给出了高红移时Ly-α发射原始星系(PG)的预期表面密度的模型计算。我们假设椭圆星系和旋涡星系(=球体)是在宇宙早期形成的，发射PG的Ly-α是在高红移恒星形成的第一次爆发时的这些球体。模型的主要假设之一是，由于尘埃的快速形成，球体中第一次恒星爆发的Ly-α亮相被限制在其开始后的一段短时间内。这些模型不仅解释了Ly-α发射PG的早期调查失败的原因，而且也符合新调查的限制(例如，Calar Alto深度成像调查-CADIS)。在微弱探测限S Lim≤10−20Wm−2下，Ly-α发射体的面密度在z=3a和z=6之间的红移范围内变化不大，在Z0≈4时达到最大值。在较浅的探测限下，S Lim≥3×10−20Wm−2高z Ly-α发射体的面密度有望成为红移和探测下限的陡峭函数。这解释了为什么在z>；5发现明亮的Ly-α星系的成功率很低。我们演示了从最近的观测中得到的Ly-α发射PG的表面密度是如何制约我们模型的参数的。最后，我们讨论了星系形成过程中出现两个Ly-α亮相的可能性：一个是尘埃几乎不存在的初始原始阶段，另一个是在一些Lyman Break星系中观察到的强星系风促进了尘埃形成后Ly-α光子逃逸的次要阶段。
We present model calculations for the expected surface density of Ly-α emitting primeval galaxies (PGs) at high redshifts. We assume that elliptical galaxies and bulges of spiral galaxies (=spheroids) formed early in the universe and that the Ly-α emitting PGs are these spheroids during their first burst of star formation at high redshift. One of the main assumptions of the models is that the Ly-α bright phase of this first starburst in the spheroids is confined to a short period after its onset due to rapid formation of dust. The models do not only explain the failure of early surveys for Ly-α emitting PGs but are also consistent with the limits of new surveys (e.g. the Calar Alto Deep Imaging Survey - CADIS). At faint detection limits S lim ≤ 10 −20 Wm −2 the surface density of Ly-α emitters is expected to vary only weakly in the redshift range between z = 3a nd z = 6 with values >10 3 /deg 2 /∆z = 0.1 reaching its maximum at z0 ≈ 4. At shallower detection limits, S lim ≥ 3 × 10 −20 Wm −2 the surface density of high-z Ly-α emitters is expected to be a steep function of redshift and detection limit. This explains the low success in finding bright Ly-α galaxies at z > 5. We demonstrate how the observed surface densities of Ly-α emitting PGs derived from recent surveys constrain the parameters of our models. Finally, we discuss the possibility that two Ly-α bright phases occur in the formation process of galaxies: An initial - primeval - phase in which dust is virtually non-existant, and a later secondary phase in which strong galactic winds as observed in some Lyman break galaxies facilitate the escape of Ly-α photons after dust has already been formed.