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arXiv 2105.03421astro-ph.CO
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来自unWISE和Planck CMB透镜层析成像的宇宙学约束

Cosmological constraints from unWISE and Planck CMB lensing tomography

Alex Krolewski, Simone Ferraro, Martin White

摘要:

最近的一些低红移的透镜测量暗示宇宙中的透镜振幅低于$Λ$ CDM模型对普朗克CMB任务数据的预测。在这里,我们使用的自相关和互相关信号的unWISE星系和普朗克CMB透镜映射来推断宇宙学参数在低红移。特别是,我们考虑三个unWISE样本(表示为“蓝色”,“绿色”和“红色”)的中位数红移$z \sim 0.6$,$1.1$和1.5,这完全覆盖了暗能量主导的时代。我们的互相关测量,结合意义$S/N \sim 80$,被用来推断低红移波动的幅度,$σ_8$ ;宇宙中物质的分数,$Ω_m$ ;和组合$S_8 \equiv σ_8 (Ω_m / 0.3)^{0.5}$,这些低红移透镜测量是最敏感的。蓝色、绿色和红色样品的组合给出了一个值$S_8=0.784\pm 0.015$,这与其他低红移透镜测量完全一致,并且在2.4 $σ$张力下与普朗克的CMB预测一致。这是值得注意的,因为CMB透镜探测与以前的星系透镜测量相同的物理,但具有非常不同的系统学,从而为以前的测量提供了一个很好的补充。

英文摘要:

A number of recent, low-redshift, lensing measurements hint at a universe in which the amplitude of lensing is lower than that predicted from the $Λ$CDM model fit to the data of the Planck CMB mission. Here we use the auto- and cross-correlation signal of unWISE galaxies and Planck CMB lensing maps to infer cosmological parameters at low redshift. In particular, we consider three unWISE samples (denoted as "blue", "green" and "red") at median redshifts $z \sim 0.6$, $1.1$ and 1.5, which fully cover the Dark Energy dominated era. Our cross-correlation measurements, with combined significance $S/N \sim 80$, are used to infer the amplitude of low-redshift fluctuations, $σ_8$; the fraction of matter in the Universe, $Ω_m$; and the combination $S_8 \equiv σ_8 (Ω_m / 0.3)^{0.5}$ to which these low-redshift lensing measurements are most sensitive. The combination of blue, green and red samples gives a value $S_8=0.784\pm 0.015$, that is fully consistent with other low-redshift lensing measurements and in 2.4$σ$ tension with the CMB predictions from Planck. This is noteworthy, because CMB lensing probes the same physics as previous galaxy lensing measurements, but with very different systematics, thus providing an excellent complement to previous measurements.

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