论文标题

CMB大规模极化图缺乏相关异常

Lack-of-correlation anomaly in CMB large scale polarisation maps

论文作者

Chiocchetta, Caterina, Gruppuso, Alessandro, Lattanzi, Massimiliano, Natoli, Paolo, Pagano, Luca

论文摘要

我们使用两点相关函数作为测试案例,对CMB进行了极化中的CMB大规模异常。我们采用了大规模极化数据集的艺术状态:基于Planck 2018 HFI 100和143 GHz跨光谱分析的第一个,基于Sroll2处理,第二个是从Planck 2018 LFI LFI和WMAP-9年的联合处理中得出的基于地图的方法。我们考虑众所周知的$ s_ {1/2} $估算器,该估计器测量了两点相关函数的距离,该函数与大于$ 60^{\ circ} $的角度尺度上的零级函数,并依靠现实的模拟来评估两个数据集来评估置信区间。 By focusing on the pure polarisation field described by either the $Q$ and $U$ Stokes parameters or by the local $E-$modes, we show that the first description is heavily influenced by the quadrupole (which is poorly constrained in both datasets) while the second one is more suited for an analysis containing higher multipoles up to $\ell \sim 10$, limit above which both datasets become markedly noise dominated.我们发现,两个数据集在纯极化中均缺乏相关的异常,类似于温度下观察到的,这更好地受到了较不嘈杂的Planck HFI 100 $ \ times $ 143的数据,其意义在于约99.5美元\%$。我们使用观察到的温度场约束或不受限制的实现进行分析,并在两种情况下找到相似的结果。

We present an assessment of the CMB large scale anomalies in polarisation using the two-point correlation function as a test case. We employ the state of the art of large scale polarisation datasets: the first based on a Planck 2018 HFI 100 and 143 GHz cross-spectrum analysis, based on SRoll2 processing, and the second from a map-based approach derived through a joint treatment of Planck 2018 LFI and WMAP-9yr. We consider the well-known $S_{1/2}$ estimator, which measures the distance of the two-point correlation function from zero at angular scales larger than $60^{\circ}$, and rely on realistic simulations for both datasets to assess confidence intervals. By focusing on the pure polarisation field described by either the $Q$ and $U$ Stokes parameters or by the local $E-$modes, we show that the first description is heavily influenced by the quadrupole (which is poorly constrained in both datasets) while the second one is more suited for an analysis containing higher multipoles up to $\ell \sim 10$, limit above which both datasets become markedly noise dominated. We find that both datasets exhibit a lack-of-correlation anomaly in pure polarisation, similar to the one observed in temperature, which is better constrained by the less noisy Planck HFI 100$\times$143 data, where its significance lies at about $99.5\%$. We perform our analysis using realizations that are either constrained or non-constrained by the observed temperature field, and find similar results in the two cases.

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