Abstract

In this work, we test the ability of an exact solution, found in the framework of a nonlinear extension of the Israel-Stewart theory, to fit the supernovae Ia, gravitational lensing, and black hole shadow data. This exact solution is a generalization of one previously found for a dissipative unified dark matter model in the context of the near-equilibrium description of dissipative processes, where we do not have the full regime of the nonlinear picture. This generalized solution is restricted to the case where a positive entropy production is guaranteed and is tested under the condition that ensures its causality, local existence, and uniqueness. From the observational constraints, we found that this generalized solution is a good candidate in the description of the observational late-time data used in this work, with best-fit values of H0=73.2-0.9+0.8km/sMpc, q0=-0.41-0.03+0.03, xi<^>0=0.88-0.17+0.09, & varepsilon;=0.34-0.04+0.03, and k=0.27-0.20+0.37, at a 1 sigma(68.3%) of confidence level. We show that the nonlinear regime of the Israel-Stewart theory consistently describes the recent accelerated expansion of the universe without the inclusion of some kind of dark energy component and also provides a more realistic description of the fluids that make up the late universe.