2012/07/31 by Julien Grain, J. Grain, M. Tristram +3
Physics and Astronomy · #Cosmology and Gravitation Theories #Particle physics theoretical and experimental studies #Radio Astronomy Observations and Technology #astro-ph.CO
paper · pdf · doi:10.1103/physrevd.86.076005
published as Phys. Rev. D 86 076005 (2012) · 23 pages, 10 figures, submitted for publication to Physical Review D
openalex publication_date 2012/10/03 · arxiv created 2012/10/17 · arxiv updated 2012/10/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/02
We discuss methods for estimating EB and TB spectra of the cosmic microwave background anisotropy maps covering limited sky area. Such odd-parity correlations are expected to vanish whenever parity is not broken. As this is indeed the case in the standard cosmologies, any evidence to the contrary would have a profound impact on our theories of the early Universe. Such correlations could also become a sensitive diagnostic of some particularly insidious instrumental systematics. In this work we introduce three different unbiased estimators based on the so-called standard and pure pseudo-spectrum techniques and later assess their performance by means of extensive Monte Carlo simulations performed for different experimental configurations. We find that a hybrid approach combining a pure estimate of B-mode multipoles with a standard one for E-mode (or T) multipoles, leads to the smallest error bars for both EB (or TB respectively) spectra as well as for the three other polarization-related angular power spectra (i.e., EE, BB, and TE). However, if both E and B multipoles are estimated using the pure technique, the loss of precision for the EB spectrum is not larger than \ensuremath∼30%. Moreover, for the experimental configurations considered here, the statistical uncertainties-due to sampling variance and instrumental noise-of the pseudo-spectrum estimates is at most a factor \ensuremath∼1.4 for TT, EE, and TE spectra and a factor \ensuremath∼2 for BB, TB, and EB spectra, higher than the most optimistic Fisher estimate of the variance.