2001/01/01 by Priyamvada Natarajan, Robert Crittenden, Robert G. Crittenden +3 · 3 citations
Physics and Astronomy · #Adaptive optics and wavefront sensing #Galaxies: Formation, Evolution, Phenomena #Radio Astronomy Observations and Technology #astro-ph
paper · pdf · doi:10.1071/as01018
published as Publ.Astron.Soc.Austral. 18 (2001) 198-200 · 4 pages, LaTeX, 2 figures, OzLens Workshop proceedings
openalex publication_date 2001/01/01 · arxiv created 2001/01/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/03
Abstract Alignments in the angular momentum vectors of galaxies can induce large scale correlations in their projected orientations. Such alignments arise from the tidal torques exerted on neighboring protogalaxies by the smoothly varying shear field. Weak gravitational lensing can also induce ellipticity correlations since the images of neighboring galaxies will be distorted coherently by the intervening mass distribution. Comparing these two sources of shape correlations, it is found that for current weak lensing surveys with a median redshift of z m = 1, the intrinsic signal is a contaminant on the order of 1–10% of the measured signal. However, for shallower surveys with z m ≤ 0.3, the intrinsic correlations dominate over the lensing signal. The distortions induced by lensing are curl-free, whereas those resulting from intrinsic alignments are not. This difference can be used to disentangle these two sources of ellipticity correlations. When the distortions are dominated by lensing, as occurs at high redshifts, the decomposition provides a valuable tool for understanding properties of the noise and systematic errors.