Is there supernova evidence for dark energy metamorphosis?
Abstract
We reconstruct the equation of state w(z) of dark energy (DE) using a recently released data set containing 172 Type Ia supernovae (SNe) without assuming the prior w(z) >=-1 (in contrast to previous studies). We find that DE evolves rapidly and metamorphoses from dust-like behaviour at high z (w~= 0 at z~ 1) to a strongly negative equation of state at present (w<~-1 at z~= 0). DE metamorphosis appears to be a robust phenomenon which manifests for a large variety of SNe data samples provided one does not invoke the weak energy prior ρ+p>= 0. Invoking this prior considerably weakens the rate of growth of w(z). These results demonstrate that DE with an evolving equation of state provides a compelling alternative to a cosmological constant if data are analysed in a prior-free manner and the weak energy condition is not imposed by hand.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2004
- DOI:
- 10.1111/j.1365-2966.2004.08189.x
- arXiv:
- arXiv:astro-ph/0311364
- Bibcode:
- 2004MNRAS.354..275A
- Keywords:
-
- methods: statistical;
- cosmological parameters;
- cosmology: theory;
- Astrophysics;
- General Relativity and Quantum Cosmology;
- High Energy Physics - Theory
- E-Print:
- 20 pages, 21 figures. Discussions enhanced. Appendix added on error propagation with new figures. References updated. Main results unchanged. Accepted for publication in MNRAS