Imprints of dynamical dark energy on weak-lensing measurements

Author: Chongchitnan Sirichai   King Lindsay  

Publisher: Oxford University Press

ISSN: 0035-8711

Source: Monthly Notices of the Royal Astronomical Society, Vol.407, Iss.3, 2010-09, pp. : 1989-1997

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Abstract

ABSTRACTWe show that simple models of scalar-field dark energy leave a generic enhancement in the weak-lensing power spectrum when compared to the Λ cold dark matter (ΛCDM) prediction. In particular, we calculate the linear-scale enhancement in the convergence (or cosmic-shear) power spectrum for two best-fitting models of scalar-field dark energy, namely the Ratra–Peebles and SUGRA-type quintessence. Our calculations are based on linear perturbation theory, using gauge-invariant variables with carefully defined adiabatic initial conditions. We find that geometric effects enhance the lensing power spectrum on a broad range of scales, whilst the clustering of dark energy gives rise to additional power on large scales. The dark-energy power spectrum for these models are also explicitly obtained. On degree scales, the total enhancement may be as large as 30–40 per cent for sources at redshift ∼1. We argue that there are realistic prospects for detecting such an enhancement using the next generation of large telescopes.

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