Model-independent dark energy differentiation with the integrated Sachs-Wolfe effect.
We study the integrated Sachs-Wolfe effect using a model-independent parametrization of the dark energy equation of state, w(z). Cosmic variance severely restricts the class of models distinguishable from one based on cold dark matter and a cosmological constant unless w(z) currently satisfies w(o)(Q)>-0.8, or exhibits a rapid, late-time, transition at redshifts z<3. Because of the degeneracy with other cosmological parameters, models with a slowly varying w(z) cannot be differentiated from each other or from a cosmological constant. This may place a fundamental limit on our understanding of the origin of the currently observed acceleration.
Corasaniti
P S
PS
Centre for Theoretical Physics, University of Sussex, Falmer, Brighton, BN1 9QJ, United Kingdom.
Bassett
B A
BA
Ungarelli
C
C
Copeland
E J
EJ