Regular Article - Theoretical Physics
Seeking evolution of dark energy
Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC, 27599-3255, USA
* e-mail: firstname.lastname@example.org
Revised: 10 August 2011
Published online: 2 September 2011
We study how observationally to distinguish between a cosmological constant (CC) and an evolving dark energy with equation of state ω(Z). We focus on the value of redshift Z ∗ at which the cosmic late time acceleration begins and . Four ω(Z) are studied, including the well-known CPL model and a new model that has advantages when describing the entire expansion era, ∞>Z>−1, such that the future 0>Z>−1 is also sensibly described. If dark energy is represented by a CC model with ω≡−1, the present ranges for Ω Λ (t 0) and Ω m (t 0) imply that Z ∗=0.743 with 4% error. We discuss the possible implications of a model-independent measurement of Z ∗ with better accuracy.
© Springer-Verlag / Società Italiana di Fisica, 2011