Blind correction of the EB-leakage in the pixel domain

Liu, Hao; Creswell, James; Dachlythra, Konstantina

doi:10.1088/1475-7516/2019/04/046

Cited by 19 publications

(18 citation statements)

References 20 publications

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“…We here introduce two independent methods; the first is a relaxation method, and the second provides a more elaborate solution utilizing our recently introduced EB-families. In [29], we provide mathematical proof that method 2 is the best blind correction of the EB-leakage in the pixel-domain, but in this work we still present the results of both methods as a useful cross-check.…”

Section: Methods and Examplesmentioning

confidence: 99%

Methods for pixel domain correction of EB leakage

Liu

Creswell²,

Hausegger³

et al. 2019

Phys. Rev. D

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In observation of the cosmic microwave background (CMB) polarization, "EB leakage" refers to the artificial B-mode signal coming from the leakage of E-mode signal when part of the sky is unavailable or excluded. Correction of such leakage is one of the preconditions for detecting primordial gravitational waves via the CMB B-mode signal. In this work, we design two independent methods for correcting the EB leakage directly in the pixel domain using standard definitions of the Eand B-modes. The two methods give consistent results, and both are fast and easy to implement. Tests on a CMB simulation containing zero initial B-mode show an efficient suppression of the EB leakage. When combined with the MASTER method to reconstruct the full-sky B-mode spectrum in simulations with a relatively simple mask, the error from EB-leakage is suppressed further by more than one order of magnitude at the recombination bump, and up to three orders of magnitude at higher multipoles, compared to a "pure" MASTER scheme under the same conditions. Meanwhile, although the final power spectrum estimation benefits from apodization, the pixel domain correction itself is done without apodization, and thus the methods offer more freedom in choosing an apodization based on specific requirements.

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Section: Methods and Examplesmentioning

confidence: 99%

Methods for pixel domain correction of EB leakage

Liu

Creswell²,

Hausegger³

et al. 2019

Phys. Rev. D

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“…Eliminating B mode caused by EB leakage is one of the most important steps in CMB data processing for CMB B mode measurement. Many literature provide effective methods for its correction on harmonic domain [29,30] or pixel domain [31][32][33]. It is worth noting that the extra B-mode caused by EB leakage will affect the implementation of ILC in polarization maps, because the B-mode caused by EB leakage will participate in the trade-off of B-modes in ILC.…”

Section: Introductionmentioning

confidence: 99%

Efficient ILC analysis on polarization maps after EB leakage correction

Zhang,

Liu,

et al. 2021

Preprint

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The Internal Linear Combination (ILC) is widely used to extract the cosmic microwave background (CMB) signal from multi-frequency observation maps, especially for Satellite experiments with quasi-full sky coverage. We extend ILC method to CMB polarization map analysis with a small sky patch which is especially typical for ground based experiments, by combing ILC with a template cleaning method which can give pure B map free from EB-leakage caused by partial sky coverage. The feature of our methods is that we do the ILC analysis on pseudo-scalar B maps, and the advantage is that it totally avoid the impact of EB leakage on ILC, so that it can improve the efficiency of component separation dramatically. We demonstrate our methods with mock data of a future ground based experiment with deep survey on a clean patch in northern sky, and the results show that the level of foreground residual can be well controlled, it bias the tensor to scalar ratio (r) at the order of 10 −3 which is comparable to statistical error by noise.

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“…However, it is important to stress, that component separation and extraction of the primordial CMB polarised signal usually takes place in Q, U domain and only then is converted into E/B components. This conversion is not local and for different masks is accompanied by the presence of different E-to-B leakage terms [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Statistics of CMB polarization angles

Creswell

Dachlythra

Liu

et al. 2020

J. Cosmol. Astropart. Phys.

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We study the distribution functions of the CMB polarization angle ψ, focusing on the Planck 2018 CMB maps. We extend the model of Preece & Battye (2014) of Gaussian correlated Q and U Stokes parameters to allow nonzero means. When the variances of Q and U are equal and their covariance and means are zero, the polarization angle is uniformly distributed. Otherwise the uniform distribution will be modulated by harmonics with 2ψ and 4ψ phases. These modulations are visible in the Planck 2018 CMB maps. Furthermore, the mean value of U is peculiar compared to the power spectrum.

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Blind correction of the EB-leakage in the pixel domain

Cited by 19 publications

References 20 publications

Methods for pixel domain correction of EB leakage

Methods for pixel domain correction of EB leakage

Efficient ILC analysis on polarization maps after EB leakage correction

Statistics of CMB polarization angles

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