https://doi.org/10.1140/epjc/s10052-013-2471-1
Regular Article - Theoretical Physics
Viscous generalized Chaplygin gas as a unified dark fluid
1
Institute of Theoretical Physics, Dalian University of Technology, Dalian, 116024, P.R. China
2
Department of Physics, Bohai University, Jinzhou, 121013, China
* e-mail: liweizhd@126.com
Received:
11
April
2013
Revised:
20
May
2013
Published online:
18
June
2013
In this paper, we revisit viscous generalized Chaplygin gas (VGCG) as a unified dark fluid, which modifies the pressure only by redefining the effective pressure p
eff, according to 
, where ζ
0 is the newly added model parameter which characterizes the viscous property and can be determined by the cosmic observations. By using the currently available cosmic observational data from WMAP, BAO, and SN Ia, the model parameter space is obtained via a Markov Chain Monte Carlo method: 
in 1, 2, 3σ regions. The results show that the viscous effect is very small due the value ζ
0≈0 and the VGCG model can match observational data points as well as ΛCDM model.
© Springer-Verlag Berlin Heidelberg and Società Italiana di Fisica, 2013
