# Statistical imprints of CMB B -type polarization leakage in an incomplete sky survey analysis

## Abstract

One of the main goals of modern cosmology is to search for primordial gravitational waves by looking on their imprints in the B -type polarization in the cosmic microwave background radiation. However, this signal is contaminated by various sources, including cosmic weak lensing, foreground radiations, instrumental noises, as well as the E -to- B leakage caused by the partial sky surveys, which should be well understood to avoid the misinterpretation of the observed data. In this paper, we adopt the E / B decomposition method suggested by Smith in 2006, and study the imprints of E -to- B leakage residuals in the constructed B -type polarization maps, B( n-circumflex ), by employing various statistical tools. We find that the effects of E -to- B leakage are negligible for the B-mode power spectrum, as well as the skewness and kurtosis analyses of B-maps. However, if employing the morphological statistical tools, including Minkowski functionals and/or Betti numbers, we find the effect of leakage can be detected at very high confidence level, which shows that in the morphological analysis, the leakage can play a significant role as a contaminant for measuring the primordial B -mode signal and must be taken into account formore »

- Authors:

- CAS Key Laboratory for Researches in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)

- Publication Date:

- OSTI Identifier:
- 22680076

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Cosmology and Astroparticle Physics

- Additional Journal Information:
- Journal Volume: 2017; Journal Issue: 01; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASYMMETRY; BACKGROUND RADIATION; COSMOLOGY; DECOMPOSITION; DISTRIBUTION; GRAVITATIONAL LENSES; GRAVITATIONAL WAVES; MINKOWSKI SPACE; NOISE; POLARIZATION; RELICT RADIATION; SPECTRA; STATISTICS

### Citation Formats

```
Santos, Larissa, Wang, Kai, Hu, Yangrui, Fang, Wenjuan, and Zhao, Wen, E-mail: larissa@ustc.edu.cn, E-mail: ljwk@mail.ustc.edu.cn, E-mail: hyr1996@mail.ustc.edu.cn, E-mail: wenjuan.fang@gmail.com, E-mail: wzhao7@ustc.edu.cn.
```*Statistical imprints of CMB B -type polarization leakage in an incomplete sky survey analysis*. United States: N. p., 2017.
Web. doi:10.1088/1475-7516/2017/01/043.

```
Santos, Larissa, Wang, Kai, Hu, Yangrui, Fang, Wenjuan, & Zhao, Wen, E-mail: larissa@ustc.edu.cn, E-mail: ljwk@mail.ustc.edu.cn, E-mail: hyr1996@mail.ustc.edu.cn, E-mail: wenjuan.fang@gmail.com, E-mail: wzhao7@ustc.edu.cn.
```*Statistical imprints of CMB B -type polarization leakage in an incomplete sky survey analysis*. United States. doi:10.1088/1475-7516/2017/01/043.

```
Santos, Larissa, Wang, Kai, Hu, Yangrui, Fang, Wenjuan, and Zhao, Wen, E-mail: larissa@ustc.edu.cn, E-mail: ljwk@mail.ustc.edu.cn, E-mail: hyr1996@mail.ustc.edu.cn, E-mail: wenjuan.fang@gmail.com, E-mail: wzhao7@ustc.edu.cn. Sun .
"Statistical imprints of CMB B -type polarization leakage in an incomplete sky survey analysis". United States. doi:10.1088/1475-7516/2017/01/043.
```

```
@article{osti_22680076,
```

title = {Statistical imprints of CMB B -type polarization leakage in an incomplete sky survey analysis},

author = {Santos, Larissa and Wang, Kai and Hu, Yangrui and Fang, Wenjuan and Zhao, Wen, E-mail: larissa@ustc.edu.cn, E-mail: ljwk@mail.ustc.edu.cn, E-mail: hyr1996@mail.ustc.edu.cn, E-mail: wenjuan.fang@gmail.com, E-mail: wzhao7@ustc.edu.cn},

abstractNote = {One of the main goals of modern cosmology is to search for primordial gravitational waves by looking on their imprints in the B -type polarization in the cosmic microwave background radiation. However, this signal is contaminated by various sources, including cosmic weak lensing, foreground radiations, instrumental noises, as well as the E -to- B leakage caused by the partial sky surveys, which should be well understood to avoid the misinterpretation of the observed data. In this paper, we adopt the E / B decomposition method suggested by Smith in 2006, and study the imprints of E -to- B leakage residuals in the constructed B -type polarization maps, B( n-circumflex ), by employing various statistical tools. We find that the effects of E -to- B leakage are negligible for the B-mode power spectrum, as well as the skewness and kurtosis analyses of B-maps. However, if employing the morphological statistical tools, including Minkowski functionals and/or Betti numbers, we find the effect of leakage can be detected at very high confidence level, which shows that in the morphological analysis, the leakage can play a significant role as a contaminant for measuring the primordial B -mode signal and must be taken into account for a correct explanation of the data.},

doi = {10.1088/1475-7516/2017/01/043},

journal = {Journal of Cosmology and Astroparticle Physics},

issn = {1475-7516},

number = 01,

volume = 2017,

place = {United States},

year = {2017},

month = {1}

}