arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1609.00301astro-ph.CO
收藏

空洞在宇宙微波背景上的透镜效应和温度印记

The lensing and temperature imprints of voids on the Cosmic Microwave Background

Yan-Chuan Cai, Mark Neyrinck, Qingqing Mao, John A. Peacock, Istvan Szapudi, Andreas A. Berlind

摘要:

我们已经在宇宙微波背景辐射中,在普朗克温度图和透镜会聚图中寻找了宇宙空洞的特征;空洞在这两个图中都应该是递减的。我们使用来自DR 12 SDSS CMASS星系样本的Zobov空洞。我们的分析基于N体模拟,以避免后验偏差。我们第一次检测到CMB透镜效应中的空洞特征:其意义是$3.2σ$,在振幅和投影密度轮廓形状上都接近$Λ$ CDM。还观察到温度下降,具有中等显著性($2.3σ$),幅度约为预测值的6倍。这种温度信号主要是由半径在100和150 Mpc/h之间的空隙引起的,而透镜信号主要是由较小的空隙引起的-正如预期的那样;透镜直接与密度有关,而ISW取决于引力势。观测和模拟中的空隙丰度也是一致的。我们还重复了排除低显著性空隙的分析:没有检测到透镜信号,上限约为$Λ$ CDM预测的两倍。但是平均温度下降现在在$3.7σ$水平上变得非零(类似于Granett等人发现的),振幅是预测值的20倍然而,所观察到的温度对空隙尺寸的依赖性与模拟结果不一致,而透镜效应的结果与$Λ$ CDM理论一致。因此,理论和观测之间的整体张力并不支持非标准的引力理论,尽管有迹象表明来自空洞的ISW效应的幅度有所增强。

英文摘要:

We have searched for the signature of cosmic voids in the CMB, in both the Planck temperature and lensing-convergence maps; voids should give decrements in both. We use zobov voids from the DR12 SDSS CMASS galaxy sample. We base our analysis on N-body simulations, to avoid a posteriori bias. For the first time, we detect the signature of voids in CMB lensing: the significance is $3.2σ$, close to $Λ$CDM in both amplitude and projected density-profile shape. A temperature dip is also seen, at modest significance ($2.3σ$), with amplitude about 6 times the prediction. This temperature signal is induced mostly by voids with radius between 100 and 150 Mpc/h, while the lensing signal is mostly contributed by smaller voids -- as expected; lensing relates directly to density, while ISW depends on gravitational potential. The void abundance in observations and simulations agree, as well. We also repeated the analysis excluding lower-significance voids: no lensing signal is detected, with an upper limit of about twice the $Λ$CDM prediction. But the mean temperature decrement now becomes non-zero at the $3.7σ$ level (similar to that found by Granett et al.), with amplitude about 20 times the prediction. However, the observed dependence of temperature on void size is in poor agreement with simulations, whereas the lensing results are consistent with $Λ$CDM theory. Thus, the overall tension between theory and observations does not favour non-standard theories of gravity, despite the hints of an enhanced amplitude for the ISW effect from voids.

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。

↑