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Model-independent dark energy differentiation with the ISW effect

P. S. Corasaniti·B. A. Bassett·C. Ungarelli·E. J. Copeland
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Abstract

We study the integrated Sachs-Wolfe (ISW) effect using a model-independent parameterization of the dark energy equation of state. Cosmic variance severely restricts the class of models distinguishable from Lambda-CDM. In particular if the present value of the equation of state satisfies w_Q^o <-0.8, the only distinguishable models are those with a rapidly varying equation of state, characterized by a late transition occurring at redshifts z<3. Due to the degeneracy with other cosmological parameters, models with a slowly varying behavior cannot be differentiated from each other or from a cosmological constant using even cosmic variance-limited CMB measurements. This may place a fundamental limit on our understanding of the origin of the presently observed acceleration.

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P. S. Corasaniti, B. A. Bassett, C. Ungarelli, E. J. Copeland. 2003-01-27. Model-independent dark energy differentiation with the ISW effect. https://doi.org/10.1103/physrevlett.90.091303

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