Journal Article

3D photometric cosmic shear

T. D. Kitching, A. F. Heavens and L. Miller

in Monthly Notices of the Royal Astronomical Society

Published on behalf of The Royal Astronomical Society

Volume 413, issue 4, pages 2923-2934
Published in print June 2011 | ISSN: 0035-8711
Published online May 2011 | e-ISSN: 1365-2966 | DOI:
3D photometric cosmic shear

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Here we present a number of improvements to weak lensing 3D power spectrum analysis, 3D cosmic shear, that uses the shape and redshift information of every galaxy to constrain cosmological parameters. We show how photometric redshift probability distributions for individual galaxies can be directly included in this statistic with no averaging. We also include the Limber approximation, considerably simplifying full 3D cosmic shear analysis, and we investigate its range of applicability. Finally we show the relationship between weak lensing tomography and the 3D cosmic shear field itself; the steps connecting them being the Limber approximation, a harmonic-space transform and a discretization in wavenumber. Each method has its advantages; 3D cosmic shear analysis allows straightforward inclusion of all relevant modes, thus ensuring minimum error bars, and direct control of the range of physical wavenumbers probed, to avoid the uncertain highly non-linear regime. On the other hand, tomography is more convenient for checking systematics through direct investigation of the redshift dependence of the signal. Finally, for tomography, we suggest that the angular modes probed should be redshift dependent, to recover some of the 3D advantages.

Keywords: cosmology: theory; large-scale structure of Universe

Journal Article.  7642 words.  Illustrated.

Subjects: Astronomy and Astrophysics

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