Observational constraints on unified dark matter including Hubble parameter data
- 作者：Kai Liao ; Shuo Cao ; Jun Wang ; Xiaolong Gong ; Zong-Hong Zhu ; zhuzh@bnu.edu.cn
- 关键词：Unified dark matter ; Affine equation ; Hubble parameter
- 刊名：Physics Letters B
- 出版年：2012
- 期刊代码：58_03702693
- 类别：ph
- 出版时间：29 March, 2012
- 卷：710
- 期：1
- 页码：17-25
- 文件大小：783 K
摘要
We constrain a unified dark matter (UDM) model from the latest observational data. This model assumes that the dark sector is degenerate. Dark energy and dark matter are the same component. It can be described by an affine equation of state . Our data set contains the newly revised data, type Ia supernovae (SNe Ia) from Union2 set, baryonic acoustic oscillation (BAO) observation from the spectroscopic Sloan Digital Sky Survey (SDSS) data release 7 (DR7) galaxy sample, as well as the cosmic microwave background (CMB) observation from the 7-year Wilkinson Microwave Anisotropy Probe (WMAP7) results. By using the Markov Chain Monte Carlo (MCMC) method, we obtain the results in a flat universe: , , . Moreover, when considering a non-flat universe, , , , . These give a more stringent results than before. We also give the results from other combinations of these data for comparison. The observational Hubble parameter data can give a more stringent constraint than SNe Ia. From the constraint results, we can see the parameters 伪 and are very close to zero, which means a flat universe is strongly supported and the speed of sound of the dark sector seems to be zero.