Volume 488, Number 1, September II 2008
|Page(s)||47 - 53|
|Section||Cosmology (including clusters of galaxies)|
|Published online||27 May 2008|
What can be learned about dark energy evolution?
Institut d'Astrophysique Spatiale (IAS), Univ. Paris-Sud, CNRS, Bâtiment 121, 91405 Orsay, France e-mail: firstname.lastname@example.org
2 Laboratoire d'Annecy-le-Vieux de Physique des Particules, UMR 5814 CNRS, 9 chemin de Bellevue, BP 110, 74941 Annecy-le-Vieux Cedex, France e-mail: email@example.com
3 LATT, Université de Toulouse, CNRS, 14 avenue É. Belin, 31400 Toulouse, France e-mail: firstname.lastname@example.org
4 CNRS, UMR 7095, Institut d'Astrophysique de Paris, 75014 Paris, France; Université Pierre et Marie Curie-Paris 6, UMR 7095, 75014 Paris, France e-mail: email@example.com
Accepted: 22 April 2008
We examine constraints obtained from SNIa surveys on a two parameter model of dark energy in which the equation of state undergoes a transition over a period significantly shorter than the Hubble time. We find that a transition between and (the first value being somewhat arbitrary) is allowed at redshifts as low as 0.1, despite the fact that data extend beyond . Surveys with the precision anticipated for space experiments should allow only slight improvement on this constraint, as a transition occurring at a redshift as low as ~0.17 could still remain undistinguishable from a standard cosmological constant. The addition of a prior on the matter density only modestly improves the constraints. Even deep space experiments would still fail to identify a rapid transition at a redshift above 0.5. These results illustrate that a Hubble diagram of distant SNIa alone will not reveal the actual nature of dark energy at a redshift above 0.2 and that only the local dynamics of the quintessence field can be inferred from a SNIa Hubble diagram. Combinations, however, seem to be very efficient: we found that the combination of present day CMB data and SNIa already excludes a transition at redshifts below 0.8.
Key words: cosmology: cosmic microwave background / cosmology: cosmological parameters / cosmology: observations
© ESO, 2008
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.