2006/04/30 by Eric V. Linder · 3 citations
Physics and Astronomy · #astro-ph
paper · pdf · doi:10.1016/j.astropartphys.2006.05.004
published as Astropart.Phys. 26 (2006) 102-110 · 9 pages, 6 figures; minor changes (cooler Fig. 1) to match Astroparticle Physics version
arxiv created 2006/06/19 · arxiv updated 2009/12/01
In the quest for precision cosmology, one must ensure that the cosmology is accurate as well. We discuss figures of merit for determining from observations whether the dark energy is a cosmological constant or dynamical, with special attention to the best determined equation of state value, at the ``pivot'' or decorrelation redshift. We show this is not necessarily the best lever on testing consistency with the cosmological constant, and moreover is subject to bias. The standard parametrization of w(a)=w0+wa(1-a) by contrast is quite robust, as tested by extensions to higher order parametrizations and modified gravity. Combination of complementary probes gives strong immunization against inaccurate, but precise, cosmology.