2015/11/04 by Yifan Wang, Yi-Fan Wang, Kai Wang +1
Mathematics · Physics and Astronomy · #Algorithm #Anisotropy #Astrophysics #COSMIC cancer database #Computational physics #Computer science #Cosmic microwave background #Cosmology and Gravitation Theories #Enhanced Data Rates for GSM Evolution #Galaxies: Formation, Evolution, Phenomena #Gaussian #Leakage (economics) #Mathematics #Mode (computer interface) #Optics #Physics #Polarization (electrochemistry) #Quantum mechanics #Radio Astronomy Observations and Technology #Smoothing #Statistical physics #Statistics #Telecommunications #astro-ph.CO
paper · pdf · doi:10.1088/1674-4527/16/4/059
published as Research in Astronomy and Astrophysics 16, 4 (2016) · 14 pages, 7 figures, RAA accepted
arxiv created 2015/11/04 · openalex publication_date 2016/04/01 · arxiv updated 2016/05/19 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
The anisotropies of the B -mode polarization in the cosmic microwave background radiation play a crucial role in the study of the very early Universe. However, in real observations, a mixture of the E -mode and B -mode can be caused by partial sky surveys, which must be separated before being applied to a cosmological explanation. The separation method developed by Smith (2006) has been widely adopted, where the edge of the top-hat mask should be smoothed to avoid numerical errors. In this paper, we compare three different smoothing methods and investigate leakage residuals of the E-B mixture. We find that, if less information loss is needed and a smaller region is smoothed in the analysis, the sin- and cos-smoothing methods are better. However, if we need a cleanly constructed B -mode map, the larger region around the mask edge should be smoothed. In this case, the Gaussian -smoothing method becomes much better. In addition, we find that the leakage caused by numerical errors in the Gaussian -smoothing method is mostly concentrated in two bands, which is quite easy to reduce for further E-B separations.