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arXiv 1905.09288astro-ph.CO
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$\bar T$：一个新的宇宙学参数？

$\bar T$: A New Cosmological Parameter?

Jaiyul Yoo, Ermis Mitsou, Yves Dirian, Ruth Durrer

备注：
5 pages, 2 figures, published in PRD. Planck 2018 analysis is discussed
发表信息：
Phys. Rev. D 100, 063510 (2019)
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摘要：

背景光子温度$\bar T$是宇宙学的基本参数之一。尽管$\bar T$具有重要意义，但由于COBE FIRAS对喜剧微波背景（CMB）温度的精确测量，在数据分析中，它从未被允许改变。然而，即使在未来的CMB实验中，$\bar T$仍将是未知的，因为我们位置处的未知的热贡献$Θ_0$对观测到的（角度平均）温度$\langle T\rangle^{\rm obs}$的贡献是未知的。通过固定$\bar T\equiv\langle T\rangle^{\rm obs}$，标准分析低估了宇宙学参数的误差线，并且在分析中获得的最佳拟合参数与$Θ_0$的未知幅度成比例地有偏差。使用Fisher公式，我们发现这些系统误差小于来自$Planck$卫星的误差条。然而，使用$\bar T\equiv\langle T\rangle^{\rm obs}$，这些系统误差将始终存在且不可减少，未来的宇宙学调查可能会误解测量结果。

英文摘要：

The background photon temperature $\bar T$ is one of the fundamental cosmological parameters. Despite its significance, $\bar T$ has never been allowed to vary in the data analysis, owing to the precise measurement of the comic microwave background (CMB) temperature by COBE FIRAS. However, even in future CMB experiments, $\bar T$ will remain unknown due to the unknown monopole contribution $Θ_0$ at our position to the observed (angle-averaged) temperature $\langle T\rangle^{\rm obs}$. By fixing $\bar T\equiv\langle T\rangle^{\rm obs}$, the standard analysis underestimates the error bars on cosmological parameters, and the best-fit parameters obtained in the analysis are biased in proportion to the unknown amplitude of $Θ_0$. Using the Fisher formalism, we find that these systematic errors are smaller than the error bars from the $Planck$ satellite. However, with $\bar T\equiv\langle T\rangle^{\rm obs}$, these systematic errors will always be present and irreducible, and future cosmological surveys might misinterpret the measurements.

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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