LRS Bianchi Type II Bulk Viscous Fluid String Dust Magnetized Dark Energy Cosmological Model in Rosens Bimetric Theory of Gravitation with the Term-\lambda

Resumo

This work investigates the LRS (Locally Rotationally Symmetric) Bianchi Type II cosmological framework that incorporates bulk-viscous fluid, string dust, a magnetized component, and a time-dependent cosmological term ( ) within Rosen’s bimetric theory of gravitation (BTG). By solving field equations developed by Rosen’s, we construct exact solutions that describe the dynamical evolution of an anisotropic universe influenced by bulk viscosity, cosmic strings, magnetic fields, and dark energy. The analysis highlights the role of  in driving the late-time acceleration of cosmic expansion, examines the transformation from a decelerated to an accelerated phase, and explores anisotropic dark energy dominated epochs. The results of our model provide insights into how magnetic fields, cosmic strings, and dark energy influence the universe’s structure, background radiation, and evolution in alternative gravity theories. Furthermore, the geometric and physical properties of the model are examined under both power-law and exponential-law expansions.