https://doi.org/10.1140/epjc/s10052-014-3178-7
Regular Article - Theoretical Physics
Revisiting the holographic dark energy in a non-flat universe: alternative model and cosmological parameter constraints
1
Department of Physics, College of Sciences, Northeastern University, Shenyang, 110004, China
2
Center for High Energy Physics, Peking University, Beijing, 100080, China
* e-mail: zhangxin@mail.neu.edu.cn
Received:
24
September
2014
Accepted:
11
November
2014
Published online:
25
November
2014
We propose an alternative model for the holographic dark energy in a non-flat universe. This new model differs from the previous one in that the IR length cutoff 
is taken to be exactly the event horizon size in a non-flat universe, which is more natural and theoretically/conceptually concordant with the model of holographic dark energy in a flat universe. We constrain the model using the recent observational data including the type Ia supernova data from SNLS3, the baryon acoustic oscillation data from 6dF, SDSS-DR7, BOSS-DR11, and WiggleZ, the cosmic microwave background data from Planck, and the Hubble constant measurement from HST. In particular, since some previous studies have shown that the color–luminosity parameter 
of supernovae is likely to vary during the cosmic evolution, we also consider such a case that in SNLS3 is time-varying in our data fitting. Compared to the constant case, the time-varying case reduces the value of 
by about 35 and results in that deviates from a constant at about 5
level, well consistent with the previous studies. For the parameter 
of the holographic dark energy, the constant fit gives 
and the time-varying fit yields 
. In addition, an open universe is favored (at about 2) for the model by the current data.
© SIF and Springer-Verlag Berlin Heidelberg, 2014
