Viscous GCG ( generalized Chaplygin gas ) cosmology is discussed , assuming that there is bulk viscosity in the linear barotropic fluid and GCG .
The dynamical analysis indicates that the phase w _ { g } = -1 + \sqrt { 3 } \gamma \kappa \tau _ { g } / ( \gamma - \sqrt { 3 } \kappa \tau _ { \gamma } ) is a dynamical attractor and the equation of state of GCG approaches it from either w _ { g } > -1 or w _ { g } < -1 depending on the choice of its initial cosmic density parameter and the ratio of pressure to critical energy density .
Obviously , the equation of state w _ { g } can cross the boundary w _ { g } = -1 .
Also , from the point of view of dynamics , the parameters of viscous GCG should be in the range of \gamma > \sqrt { 3 } \kappa \tau _ { \gamma } / ( 1 - \sqrt { 3 } \kappa \tau _ { g } ) and 0 < \alpha < 1 + \sqrt { 3 } \kappa \gamma \tau _ { g } / ( \gamma - \sqrt { 3 } \kappa \tau _ { \gamma } - % \sqrt { 3 } \kappa \gamma \tau _ { g } ) .