Lyα Resonant Scattering in Young Galaxies: Predictions from Cosmological Simulations
Lyα Resonant Scattering in Young Galaxies: Predictions from Cosmological Simulations
复制标题
年轻星系中的 Lyα 共振散射：宇宙学模拟的预测
DOI：
10.1086/513191
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
J. Sommer
中科院分区：
文献类型：
--
作者：
P. Laursen;J. Sommer
我们介绍了用三维Lyα辐射传输代码获得的结果，该代码应用于完全宇宙学星系形成模拟。所开发的蒙特卡罗代码能够处理任意分布的源Lyα发射、中性氢密度、温度和星际介质的特殊速度。我们研究了共振散射对年轻星系外观和性质的影响，通过应用代码模拟了一个红移z = 3.6，恒星形成速率22 M☉yr-1，总Lyα光度2.0 × 1043 ergs -1的“Lyman破碎星系”。发现Lyα辐射的共振散射可以解释年轻星系在天空中经常被观测到比在光学中更延伸。此外，对于所研究的系统，由于光子的各向异性逃逸，观测到的最大表面亮度可以相差超过一个数量级，并且根据系统相对于观察者的方向，总衍生光度可以相差约4倍。
We present results obtained with a three-dimensional, Lyα radiative transfer code applied to a fully cosmological galaxy formation simulation. The developed Monte Carlo code is capable of treating an arbitrary distribution of source Lyα emission, neutral hydrogen density, temperature, and peculiar velocity of the interstellar medium. We investigate the influence of resonant scattering on the appearance and properties of young galaxies by applying the code to a simulated "Lyman break galaxy" at redshift z = 3.6, star formation rate 22 M☉ yr-1, and total Lyα luminosity 2.0 × 1043 ergs s-1. It is found that resonant scattering of Lyα radiation can explain that young galaxies are frequently observed to be more extended on the sky in Lyα than in the optical. Moreover, it is shown that, for the system investigated, due to the anisotropic escape of the photons, the observed maximum surface brightness can differ by more than an order of magnitude, and the total derived luminosity by a factor of ~4, depending on the orientation of the system relative to the observer.