Abstract
We have reanalyzed constraints on the equation of state parameter, of the dark energy, using several cosmological data sets and relaxing the usual constraint We find that combining cosmic microwave background, large scale structure, and type Ia supernova data yields a nontrivial lower bound on At 95.4% confidence we find, assuming a flat geometry of the universe, a bound of if is taken to be a completely free parameter. Reassuringly we also find that the constraint does not significantly bias the overall allowed region for When this constraint is imposed the 95.4% confidence bound is Also, a pure cosmological constant is an excellent fit to all available data. Based on simulations of future data from the Planck CMB experiment and the SNAP and SNfactory supernova experiments we estimate that it will be possible to constrain at the 5% level in the future.
- Received 23 May 2002
DOI:https://doi.org/10.1103/PhysRevD.66.063508
©2002 American Physical Society