Constraints on Holographic Dark Energy Models Using the Differential Ages of Passively Evolving Galaxies

Abstract

Using the absolute ages of passively evolving galaxies observed at different redshifts, one can obtain the differential ages, the derivative of redshift z with respect to the cosmic time t (i.e. dz/dt). Thus, the Hubble parameter H(z) can be measured through the relation H(z) = −(dz/dt)/(1 + z). By comparing the measured Hubble parameter at different redshifts with the theoretical one containing free cosmological parameters, one can constrain current cosmological models. In this paper, we use this method to present the constraint on a spatially flat Friedmann-Robert-Walker Universe with a matter component and a holographic dark energy component, in which the parameter c plays a significant role in this dark energy model. Firstly we consider three fixed values of c=0.6, 1.0 and 1.4 in the fitting of data. If we set c free, the best fitting values are c = 0.26, Ω m0 = 0.16, h = 0.9998. It is shown that the holographic dark energy behaves like a quintom-type at the 1σ level. This result is consistent with some other independent cosmological constrains, which imply that c < 1.0 is favored. We also test the results derived from the differential ages using another independent method based on the lookback time to galaxy clusters and the age of the universe. It shows that our results are reliable.

Dark Energy

“…In [572], Yi and Zhang tested the HDE model by using the H(z) data and the LT data. They also verified that the HDE behaves like a quintom-type at 1σ…”

Observational constraint on generalized Chaplygin gas model

“…Here the observed Hubble data H (z i ) and H (z j ) are uncorrelated, for they are obtained by the observations of galaxies at different redshift. Using these nine observational Hubble data one can constrain DE models by minimizing [59][60][61][62][63][64] …”

INTERACTION BETWEEN DARK ENERGY AND DARK MATTER: OBSERVATIONAL CONSTRAINTS FROM OHD, BAO, CMB AND SNe Ia

“…40 These OHD data were also used to constrain the parameters of cosmological models 41,42 and some other relevant works. [43][44][45][46][47] For example, Wei & Zhang(2007a) compared the 9 observational H(z) data with some cosmological models with/without interaction between dark energy and dust matter and found that the OHD data with fairly large errors cannot severely constrain model parameters alone.…”