Probing the evolution of the dark energy density with future supernova surveys

Abstract

The time dependence of the dark energy density can be an important clue tothe nature of dark energy in the universe. We show that future supernovadata from dedicated telescopes (such as SNAP), when combined with data ofnearby supernovae, can be used to determine how the dark energy densityρX(z) depends onredshift, if ρX(z) is not too close to a constant. For quantitative comparison, we have done an extensivestudy of a number of dark energy models. Based on these models we have simulated datasets in order to show that we can indeed reconstruct the correct sign of the timedependence of the dark energy density, outside of a degeneracy region centred on (where zmax is the maximum redshift of the survey; for example,zmax = 1.7 for SNAP).