Dark energy from large-scale structure lensing information
- Department of Astronomy and Astrophysics, University of Toronto, M5S 3H4 (Canada)
- Canadian Institute for Theoretical Astrophysics, University of Toronto, M5S 3H8 (Canada)
Wide area large-scale structure (LSS) surveys are planning to map a substantial fraction of the visible Universe to quantify dark energy through baryon acoustic oscillations. At increasing redshift, for example, that probed by proposed 21-cm intensity mapping surveys, gravitational lensing potentially limits the fidelity (Hui et al., 2007) because it distorts the apparent matter distribution. In this paper we show that these distortions can be reconstructed, and actually used to map the distribution of intervening dark matter. The lensing information for sources at z=1-3 allows accurate reconstruction of the gravitational potential on large scales, l < or approx. 100, which is well matched for integrated Sachs-Wolfe effect measurements of dark energy and its sound speed, and a strong constraint for modified gravity models of dark energy. We built an optimal quadratic lensing estimator for non-Gaussian sources, which is necessary for LSS. The phenomenon of 'information saturation' (Rimes and Hamilton, 2005) saturates reconstruction at mildly nonlinear scales, where the linear source power spectrum {Delta}{sup 2{approx}}0.2-0.5, depending on power spectrum slope. Naive Gaussian estimators with nonlinear cutoff can be tuned to reproduce the optimal non-Gaussian errors within a factor of 2. We compute the effective number densities of independent lensing sources for LSS lensing, and find that they increase rapidly with redshifts. For LSS/21-cm sources at z{approx}2-4, the lensing reconstruction is limited by cosmic variance at l < or approx. 100.
- OSTI ID:
- 21408034
- Journal Information:
- Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 12 Vol. 81; ISSN PRVDAQ; ISSN 0556-2821
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GENERAL PHYSICS
BARYONS
DENSITY
DISTRIBUTION
ELEMENTARY PARTICLES
FERMIONS
GRAVITATION
GRAVITATIONAL LENSES
HADRONS
LENSES
MATTER
NONLINEAR PROBLEMS
NONLUMINOUS MATTER
OSCILLATIONS
PHYSICAL PROPERTIES
RED SHIFT
SATURATION
SIMULATION
SOUND WAVES
SPECTRA
UNIVERSE
VELOCITY