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arXiv 1708.03068astro-ph.COastro-ph.GA
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使用平面$Λ$ CDM约束探测BAO研究

Probing BAO studies with flat $Λ$CDM constraints

Joel S. Jayson

备注：
11 pages, 7 figures, 3 tables: title change, major rewrite
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摘要：

通常用于拟合各向异性重子声振荡（BAO）的算法之一，$α_{\perp}D_{M, \text{fid}}(z)/r_{d, \text{fid}}=D_{M}(z)/r_{d}$，作为$z\Rightarrow 0$提供了极好的拟合。然而，在$ z_{\text{drag}} \simeq 1060$，$D_{M, \text{fid}}(1060)/r_{d, \text{fid}}\simeq D_{M}(1060)/r_{d}$。由于$α_{\perp}$不随红移的增加而改变，我们得出结论，随着$z$的增加，算法偏离真实的解决方案。我们调查，通过一个平坦的$Λ$ CDM宇宙学的假设偏离。在相对较低的红移在各向同性BAO研究进行，发散小于研究的不确定性。然而，虽然横向措施，$α_{\perp}$提供了一个可靠的值在真实的空间，不受红移失真，各向同性措施，$α$，有一个径向分量，并受到红移失真。这种扭曲建议在宇宙学参数评估中不要包括各向同性研究。在高红移的Ly $α$森林BAO研究，$z\sim$ 2.35，各向异性的BAO算法从平坦的$Λ$ CDM解决方案的偏差引起明显的欺骗性的结果。我们复制一个例子，其中这些算法导致的值$Ω_{m}$这是超过15%，低于单位$Λ$ CDM宇宙学计算。BAO算法不适用于下一代BAO研究。一个扁平的$Λ$ CDM分析提供了另一种评估方法。

英文摘要：

One of the algorithms typically used for fitting anisotropic Baryon Acoustic Oscillations (BAO), $α_{\perp}D_{M, \text{fid}}(z)/r_{d, \text{fid}}=D_{M}(z)/r_{d}$, provides an excellent fit as $z\Rightarrow 0$. Yet, at $ z_{\text{drag}} \simeq 1060$, $D_{M, \text{fid}}(1060)/r_{d, \text{fid}}\simeq D_{M}(1060)/r_{d}$. Since $α_{\perp}$ does not change with increasing redshift, we conclude that the algorithms deviate from true solutions with increasing $z$. We investigate that departure through an assumption of a flat $Λ$CDM cosmology. At the relatively low redshifts at which isotropic BAO studies were performed, the divergence is smaller than study uncertainties. However, while the transverse measure, $α_{\perp}$ provides a reliable value in real space, not corrupted by redshift distortion, the isotropic measure, $α$, has a radial component, and is influenced by redshift distortion. That distortion recommends against the inclusion of isotropic studies in cosmological parameter evaluations. At the high redshifts of Ly$α$ forest BAO studies, $z\sim$ 2.35, the deviations of the anisotropic BAO algorithms from the flat $Λ$CDM solutions give rise to markedly deceptive results. We replicate an example, in which those algorithms lead to a value of $Ω_{m}$ which is more than 15 per cent lower than that of the flat $Λ$CDM cosmology computation. The BAO algorithms are inappropriate for the next generation of BAO studies. A flat $Λ$CDM analysis offers an alternative means of assessment.

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