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arXiv 2010.04567astro-ph.CO
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用后重建星系双谱约束红移空间中的原始非高斯性

Constraining Primordial Non-Gaussianity with Post-reconstructed Galaxy Bispectrum in Redshift Space

Masato Shirasaki, Naonori S. Sugiyama, Ryuichi Takahashi, Francisco-Shu Kitaura

备注：
10 pages, 5 figures, 1 table. Accepted for publication in Phys. Rev. D
发表信息：
Phys. Rev. D 103, 023506 (2021)
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摘要：

星系双谱是研究早期宇宙暴胀物理的一个很有前途的工具，它可以作为原初非高斯性（PNG）的度量，但其信噪比受非线性引力增长引起的模耦合的影响很大。本文研究了从非线性星系密度场重建线性宇宙质量密度场的标准方法，以消除红移空间星系双谱的协方差。特别是，我们使用4000个独立的$N$体模拟重建的双谱的协方差星系大小的暗物质晕。我们的结果表明，双谱协方差的重建后的字段接近高斯预测的尺度为$k<0.2\, h\, {\rm Mpc}^{-1}$。我们还验证了前导阶PNG诱导的双谱不受微扰理论重建细节的影响。然后，我们证明了约束功率的后重建的双谱PNG的红移$\sim0.5$。此外，我们进行了Fisher分析，使预测的PNG约束星系双谱包括各向异性信号。假设SDSS重子振荡谱巡天中的一个大质量星系样本，我们发现后重建的双谱可以分别用$Δf_{\rm NL} \sim$ 13、90和42来约束PNG的局域型、等边型和正交型，使前重建的双谱的约束提高了$1.3-3.2$倍.总之，重建起着至关重要的作用，在约束各种类型的PNG签名与$Δf_{\rm NL}<1$的水平从星系双谱的基础上即将到来的星系调查。

英文摘要：

Galaxy bispectrum is a promising probe of inflationary physics in the early universe as a measure of primordial non-Gaussianity (PNG), whereas its signal-to-noise ratio is significantly affected by the mode coupling due to non-linear gravitational growth. In this paper, we examine the standard reconstruction method of linear cosmic mass density fields from non-linear galaxy density fields to de-correlate the covariance in redshift-space galaxy bispectra. In particular, we evaluate the covariance of the bispectrum for massive-galaxy-sized dark matter halos with reconstruction by using 4000 independent $N$-body simulations. Our results show that the bispectrum covariance for the post-reconstructed field approaches the Gaussian prediction at scale of $k<0.2\, h\, {\rm Mpc}^{-1}$. We also verify the leading-order PNG-induced bispectrum is not affected by details of the reconstruction with perturbative theory. We then demonstrate the constraining power of the post-reconstructed bispectrum for PNG at redshift of $\sim0.5$. Further, we perform a Fisher analysis to make a forecast of PNG constraints by galaxy bispectra including anisotropic signals. Assuming a massive galaxy sample in the SDSS Baryon Oscillation Spectroscopic Survey, we find that the post-reconstructed bispectrum can constrain the local-, equilateral- and orthogonal-types of PNG with $Δf_{\rm NL} \sim$13, 90 and 42, respectively, improving the constraints with the pre-reconstructed bispectrum by a factor of $1.3-3.2$. In conclusion, the reconstruction plays an essential role in constraining various types of PNG signatures with a level of $Δf_{\rm NL}<1$ from the galaxy bispectrum based on upcoming galaxy surveys.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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