New dark energy constraints from supernovae, microwave background and galaxy clustering

Preprint

23 April 2004

preprint
Published by arXiv in arXiv

https://doi.org/10.48550/arXiv.astro-ph/0403292

Abstract

Using the spectacular new high redshift supernova observations from the HST/GOODS program and previous supernova, CMB and galaxy clustering data, we make the most accurate measurements to date of the dark energy density rho_X as a function of cosmic time, constraining it in a rather model-independent way, assuming a flat universe. We find that Einstein's vanilla scenario where rho_X(z) is constant remains consistent with these new tight constraints, and that a Big Crunch or Big Rip is more than 50 gigayears away for a broader class of models allowing such cataclysmic events. We discuss popular pitfalls and hidden priors: parametrizing the equation-of-state w_X(z) assumes positive dark energy density and no Big Crunch, and the popular parametrization w_X(z)=w_0 +w_0' z has nominally strong constraints from CMB merely because w_0' > 0 implies an unphysical exponential blow-up rho_X ~ e^{3 w_0' z}.

Keywords

All Related Versions

Version 1, 2004-03-11, ArXiv
Version 2, 2004-04-23, ArXiv
Published version: Physical Review Letters, 92 (24), 241302.

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