Constraining dark energy with the integrated Sachs-Wolfe effect

We use the integrated Sachs-Wolfe (ISW) effect, by now detectable at ∼ 5σ within the context of ΛCDM cosmologies, to place strong constraints on dynamical dark energy theories. Working within an effective field theory framework for dark energy we find that including ISW constraints from galaxy-CMB cross-correlations significantly strengthens existing large-scale structure constraints, yielding bounds consistent with ΛCDM and approximately reducing the viable parameter space by ∼ 70%. This is a direct consequence of O(1) changes induced in these cross-correlations by otherwise viable dark energy models, which we discuss in detail. We compute constraints by adapting the ΛCDM ISW likelihood from [1] for dynamical dark energy models using galaxy data from 2MASS, WISE × SuperCOSMOS, SDSS-DR12, QSOs and NVSS, CMB data from Planck 18, and BAO and RSD large scale structure measurements from BOSS and 6dF. We show constraints both in terms of EFT-inspired α_i and phenomenological μ/Σ parametrisations. Furthermore we discuss the approximations involved and related aspects of bias modelling in detail and highlight what these constraints imply for the underlying dark energy theories.