Testing dark energy paradigms with weak gravitational lensing

Abstract

Any theory invoked to explain cosmic acceleration predicts consistency relations between the expansion history, structure growth, and all related observables. Currently there exist high-quality measurements of the expansion history from Type Ia supernovae, the cosmic microwave background temperature and polarization spectra, and baryon acoustic oscillations. We can use constraints from these datasets to predict what future probes of structure growth should observe. We apply this method to predict what range of cosmic shear power spectra would be expected if we lived in a ΛCDM universe, with or without spatial curvature, and what results would be inconsistent and therefore falsify the model. Though predictions are relaxed if one allows for an arbitrary quintessence equation of state −1 ≤ w(z) ≤ 1, we find that any observation that rules out ΛCDM due to excess lensing will also rule out all quintessence models, with or without early dark energy. We further explore how uncertainties in the nonlinear matter power spectrum, e.g. from approximate fitting formulas such as Halofit, warm dark matter, or baryons, impact these limits.

Dark energy two decades after: observables, probes, consistency tests

“…The simplest approach is to calculate predictions on cosmological functions that can be measured that are consistent with current parameter constraints [86,146,147].…”

Reconstructing gravity on cosmological scales

“…We seek to reconstruct the time dependence of the EFT functions, for different models, as we discussed in the previous section. This reconstruction approach has already been successfully applied to phenomenological DE/MG properties [67][68][69][70][71][72][73][74][75][76][77] and we extend it to EFT models reconstruction.…”

“…Overall we believe that the reconstruction strategy that we discussed performs better than principal components (PC) based reconstructions [68,69,71,74]. The PC basis is obtained from forecasts around a given cosmology, usually the best fitting ΛCDM one, relies on the Gaussianity of the parameter posterior and when truncated is not guaranteed to be able to describe statistically significant deviations from it.…”

Cosmological Constraints From Galaxy Clusters in the 2500 Square-Degree SPT-Sz Survey

“…Taken together, growth-based and geometrical probes can place significantly tighter constraints on parameters such as the equation of state of dark energy than either one independently, because of nearly orthogonal parameter degeneracies. Considered independently, these constraints provide a consistency test of the dark energy paradigm and the validity of general relativity (Ishak et al 2006;Mortonson et al 2009Mortonson et al , 2010Rapetti et al 2009Rapetti et al , 2010Zhan et al 2009;Acquaviva & Gawiser 2010;Vanderveld et al 2012).…”