arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1806.02789astro-ph.CO
收藏

基于地图的星系团功率谱系统模消除方法及其在BOSS中的应用

A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS

B. Bahr-Kalus, W. J. Percival, D. J. Bacon, E. -M. Mueller, L. Samushia, L. Verde, A. J. Ross, J. L. Bernal

摘要:

我们开发了一种实用的方法来消除模式从星系调查功率谱与系统误差。我们将其应用于BOSS CMASS样本,看看它是否消除了之前在非常大的尺度上观察到的超出最佳拟合$Λ$ CDM模型的多余功率。我们考虑了几种可能的数据污染源,并检查它们是否影响可以观察到的目标数量和功率谱测量。我们描述了一个一般框架,这些知识可以转化为模板字段。模式减法可以用来去除这些系统的污染物,至少以及应用校正加权所观察到的星系,但受益于提供一个公正的权力。即使在对所有已知的系统学应用模板之后,我们也发现了大规模的功率过剩,但与使用BOSS团队提供的权重所观察到的相比,这是减少的。这一超出的范围比BAO范围大得多,不影响BOSS的主要结果。然而,这将是重要的尺度依赖的偏差,由于原始的非高斯测量。超出的部分超出了任何简单的非高斯模型匹配普朗克数据所允许的范围,并且在其他调查中没有匹配。我们表明,这种功率过剩可以进一步减少,但仍然存在使用“现象学”模板,旨在考虑进一步潜在的未知来源的系统污染。由于所有不一致的角模式可以使用“现象学”模板去除,潜在的残留污染物径向作用。

英文摘要:

We develop a practical methodology to remove modes from a galaxy survey power spectrum that are associated with systematic errors. We apply this to the BOSS CMASS sample, to see if it removes the excess power previously observed beyond the best-fit $Λ$CDM model on very large scales. We consider several possible sources of data contamination, and check whether they affect the number of targets that can be observed and the power spectrum measurements. We describe a general framework for how such knowledge can be transformed into template fields. Mode subtraction can then be used to remove these systematic contaminants at least as well as applying corrective weighting to the observed galaxies, but benefits from giving an unbiased power. Even after applying templates for all known systematics, we find a large-scale power excess, but this is reduced compared with that observed using the weights provided by the BOSS team. This excess is at much larger scales than the BAO scale and does not affect the main results of BOSS. However, it will be important for the measurement of a scale-dependent bias due to primordial non-Gaussianity. The excess is beyond that allowed by any simple model of non-Gaussianity matching Planck data, and is not matched in other surveys. We show that this power excess can further be reduced but is still present using "phenomenological" templates, designed to consider further potentially unknown sources of systematic contamination. As all discrepant angular modes can be removed using "phenomenological" templates, the potentially remaining contaminant acts radially.

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。

↑