Efficient evaluation of angular power spectra and bispectra
Efficient evaluation of angular power spectra and bispectra
复制标题
角功率谱和双谱的高效评估
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Zaldarriaga
中科院分区：
文献类型：
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作者：
Valentin Assassi;M. Simonović;M. Zaldarriaga
宇宙学观测量的角统计很难计算。主要的困难是由于存在的高度振荡的贝塞尔函数，需要集成。本文提供了一种计算任意观测量的角功率谱和角双谱的简单、快速的方法。该方法是基于使用FFTlog算法分解的动量空间统计到幂律函数的基础上。对于每一个幂律，贝塞尔函数上的积分都有一个简单的解析解。这使我们能够有效地评估这些积分，独立于多极子的值。特别是，这种方法显着加快了评估的角度双谱相比，现有的方法。为了说明我们的算法，我们计算了星系，透镜和CMB温度角功率谱和双谱。
Angular statistics of cosmological observables are hard to compute. The main difficulty is due to the presence of highly-oscillatory Bessel functions which need to be integrated over. In this paper, we provide a simple and fast method to compute the angular power spectrum and bispectrum of any observable. The method is based on using an FFTlog algorithm to decompose the momentum-space statistics onto a basis of power-law functions. For each power law, the integrals over Bessel functions have a simple analytical solution. This allows us to efficiently evaluate these integrals, independently of the value of the multipole ℓ. In particular, this method significantly speeds up the evaluation of the angular bispectrum compared to existing methods. To illustrate our algorithm, we compute the galaxy, lensing and CMB temperature angular power spectrum and bispectrum.
影响因子：
6.4
作者：
L. D. L. Bella-L.-D.-L.-Bella-120849959;D. Regan;D. Seery;S. Hotchkiss
通讯作者：
L. D. L. Bella-L.-D.-L.-Bella-120849959;D. Regan;D. Seery;S. Hotchkiss