2003/05/31 by Peter Schneider, P. C. Schneider · 42 citations
Physics and Astronomy · #Astrophysics #COSMIC cancer database #Cosmic microwave background #Cosmic variance #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Mathematical physics #Parity (physics) #Physics #Pulsars and Gravitational Waves Research #Quantum mechanics #astro-ph
paper · pdf · doi:10.1051/0004-6361:20031035
published in Astronomy and Astrophysics 408(3), 829-834 (EDP Sciences) · 6 pages, no figures, minor changes to match the paper published in Astronomy & Astrophysics 408, 829--834
openalex publication_date 2003/09/01 · arxiv created 2003/09/18 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We consider the parity transformation and the consequences of parity invariance on the n-point correlation function of the cosmic shear caused by gravitational lensing by the large-scale structure, or any other polar (or “spin-2”) field. The decomposition of the shear field into E- and B-modes then yields the result that any correlation function which contains an odd number of B-mode shear components vanishes for parity-invariant random shear fields. In particular, this result implies that the expectation value of the third-order cross aperture statistics, , vanishes for parity-invariant shear fields. Therefore, a significant detection of a non-zero value of in a cosmic shear survey does not indicate the presence of B-modes, but of an underestimate of the statistical uncertainty or cosmic variance, or a remaining systematic effect in the shear measurement. We argue that the parity invariance provides a very specific diagnostic of systematic effects in shear data. Our results apply as well to the linear polarization of the cosmic microwave background.