Viscous cosmology in holographic dark energy with Granda–Oliveros cut-off

We study the effect of bulk viscosity on holographic dark energy (HDE) with Granda–Oliveros infra-red cut-off. We focus on a generalized form of the bulk viscous coefficient which successfully describes the present-day evolution of the Universe. We observe that the model with bulk viscosity provides an elegant description of the early and late-time evolution of the Universe. We constrain the model through the combined observational data of the Strong Lensing System (SLS), measurements of Hubble parameter, Type Ia supernova data of Pantheon sample and local H 0 measured by SH0ES. Using best-fit values obtained from two different combinations of data, we estimate the present value of Hubble’s constant H 0 = 71.567 − 0.848 + 1.448 and H 0 = 69.197 − 1.924 + 1.563 , the deceleration parameter q 0 = − 0.535 − 0.016 + 0.016 and q 0 = − 0.536 − 0.016 + 0.016 , and the equation of state ω 0 = − 0.690 − 0.010 + 0.010 and ω 0 = − 0.691 − 0.011 + 0.011 , respectively. The HDE model with bulk viscosity exhibits the phase transition from decelerated epoch to accelerated epoch. A comparison of the model with the standard Λ CDM model is discussed with the statefinder and cosmographic parameters.