REIONIZATION ON LARGE SCALES. IV. PREDICTIONS FOR THE 21 cm SIGNAL INCORPORATING THE LIGHT CONE EFFECT
REIONIZATION ON LARGE SCALES. IV. PREDICTIONS FOR THE 21 cm SIGNAL INCORPORATING THE LIGHT CONE EFFECT
复制标题
DOI：
10.1088/0004-637x/789/1/31
复制
发表时间：
2013-09
期刊：
影响因子：
--
通讯作者：
P. Plante;N. Battaglia;A. Natarajan;J. Peterson;H. Trac;R. Cen;A. Loeb
中科院分区：
文献类型：
--
作者：
P. Plante;N. Battaglia;A. Natarajan;J. Peterson;H. Trac;R. Cen;A. Loeb
我们提出的21厘米的亮度温度功率谱的再电离时期（EoR）的预测。我们讨论的“光锥”效应，其中包括中性氢馏分和21厘米亮度温度沿着视线的演变的影响。使用一种针对辐射流体动力学模拟校准的新方法，我们模拟了大体积（L = 2 Gpc h−1）的中性氢密度场和21 cm信号。光锥效应的列入导致在所有尺度上的21厘米功率谱中约50%的相对减少。我们还发现，在再电离的中点和更晚的时间，这种影响更加突出。光锥效应还可以沿视线沿着引入各向异性。通过将三维功率谱分解为垂直于视线和沿着视线的分量，我们发现在我们的基准再电离模型中，没有明显的各向异性。然而，对于较短的再电离场景，并行模式可以贡献高达40%的功率。与光锥效应相关的尺度与测量重子声学振荡的尺度相当。我们认为，由于其大的comoving规模和各向异性的引入，光锥效应是很重要的，当考虑红移空间扭曲和未来的应用程序的Alcock-Paczyovski测试宇宙学参数的测定。
We present predictions for the 21 cm brightness temperature power spectrum during the Epoch of Reionization (EoR). We discuss the implications of the “light cone” effect, which incorporates evolution of the neutral hydrogen fraction and 21 cm brightness temperature along the line of sight. Using a novel method calibrated against radiation-hydrodynamic simulations, we model the neutral hydrogen density field and 21 cm signal in large volumes (L = 2 Gpc h−1). The inclusion of the light cone effect leads to a relative decrease of about 50% in the 21 cm power spectrum on all scales. We also find that the effect is more prominent at the midpoint of reionization and later. The light cone effect can also introduce an anisotropy along the line of sight. By decomposing the 3D power spectrum into components perpendicular to and along the line of sight, we find that in our fiducial reionization model, there is no significant anisotropy. However, parallel modes can contribute up to 40% more power for shorter reionization scenarios. The scales on which the light cone effect is relevant are comparable to scales where one measures the baryon acoustic oscillation. We argue that due to its large comoving scale and introduction of anisotropy, the light cone effect is important when considering redshift space distortions and future application to the Alcock–Paczyński test for the determination of cosmological parameters.