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| Paper IPM / P / 14630 |
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Inspired by thermodynamical dissipative phenomena, we consider constant bulk viscosity for dark fluid in a spatially flat two-component Universe. Our viscous dark energy model represents Phantom crossing avoiding Big-Rip singularity. We propose a non-minimal derivative coupling scalar field with zero potential to describe viscous dark energy model. In this approach, coupling constant (κ) is related to viscosity coefficient (γ) and energy density of dark energy at the present time (ΩDE0). This coupling is bounded as κ ∈ [−1/9H02(1−ΩDE0), 0] and for γ = 0 leads to κ = 0. To perform robust analysis, we implement recent observational data sets including Joint Light-curve Analysis (JLA) for SNIa, Gamma Ray Bursts (GRBs) for most luminous astrophysical objects at high redshifts, Baryon Acoustic Oscillations (BAO) from different surveys, Hubble parameter from HST project, Planck data for CMB power spectrum and CMB Lensing. Joint analysis of JLA+GRBs+BAO+HST shows that ΩDE0=0.700+0.021−0.023 , γ = 0.1406+0.0064−0.0065 and H0=69.1+3.5−2.8 at 1σ confidence interval. Planck TT observation provides γ = 0.32+0.31−0.26 at 68% confidence limit for viscosity coefficient. Tension in Hubble parameter is alleviated in this model. Cosmographic distance ratio indicates that current observed data prefer to increase bulk viscosity. Finally, the competition between Phantom and Quintessence behavior of viscous dark energy model can accommodate cosmological old objects reported as a sign of age crisis in ΛCDM model.
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