One-loop perturbative corrections to the matter and galaxy bispectrum with non-Gaussian initial conditions
One-loop perturbative corrections to the matter and galaxy bispectrum with non-Gaussian initial conditions
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DOI：
10.1103/physrevd.80.123002
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发表时间：
2009-05
影响因子：
5
通讯作者：
E. Sefusatti
中科院分区：
文献类型：
--
作者：
E. Sefusatti
在非高斯初始条件下，在局部星系偏向的假设下，我们导出了宇宙学欧拉微扰理论对物质双谱和星系双谱的单圈修正的表达式。对于局域模型中非零初始双谱和初三谱的特殊情况，以及原始非高斯性等边模型中非零初始双谱的特殊情况，我们都进行了显式计算。由于大尺度上的引力不稳定，与宇宙微波背景观测相容的值对物质双谱的原始贡献占主导地位，而非高斯初始条件引起的单圈微扰修正仅对应于轻度非线性尺度上重力诱导的双谱的几个百分点，类似于物质功率谱的情况。然而，在星系双谱的微扰展开中，由非线性偏差引起的单环图对大尺度的贡献很大，对于局地模型和等边模型来说，实际上都超过了原始分量。我们研究了这种附加项对尺度和三角形组态形状的特殊依赖性，这些附加项的起源类似于最近引起人们极大兴趣的光晕和星系功率谱的大规模修正。
We derive the expressions for the one-loop corrections in cosmological, Eulerian, perturbation theory to the matter bispectrum and to the galaxy bispectrum, assuming local galaxy bias, in the presence of non-Gaussian initial conditions. We compute them explicitly for the particular case of nonvanishing initial bispectrum and trispectrum in the local model and for a nonvanishing initial bispectrum alone for the equilateral model of primordial non-Gaussianity. While the primordial contribution to the matter bispectrum for values compatible with cosmic microwave background observations is dominant over the component due to gravitational instability at large scales, one-loop perturbative corrections due to non-Gaussian initial conditions correspond to just a few percent of the gravity-induced bispectrum at mildly nonlinear scales, similar to what happens for the matter power spectrum. However, in the perturbative expansion for the galaxy bispectrum, one-loop diagrams arising from nonlinear bias are responsible for significant large-scale contributions, indeed exceeding the primordial component, both for the local and equilateral model. We study the peculiar dependence on scale and on the shape of the triangular configurations of such additional terms, similar in their origin to the large-scale corrections to the halo and galaxy power spectra that raised significant interest in the recent literature.