RETARDO TEMPORAL EN EL SISTEMA QSO 0218+357 USANDO EL MODELO DE LA ESFERA ISOTERMA CON NÚCLEO.

In this article, it is found an analytical expression for temporal retard using the isothermal sphere models with nucleus (ΔtEIN). This expression is applied or assigned to any quasar system of lensing by galaxies particularly the temporal retard is applied to the SSO 0218+357 system, using the observational values measured in the mentioned system and setting the cosmological parameters move acceptable in the literature. Because of this the temporal retard just, remains in function of the nuclear radius. Theoretically when the nuclear radius is zero, the temporal retard with nucleus (ΔtEIN), must coincide with the temporal retard of the Singular Isothermal Sphere model (ΔtEIN) in feet must be accod with the value of the temporal retard measured observationally in the mentioned system (10.1 days). It is about analyzing the sensitivity of the temporal retard with respect to the nuclear radius of the deflector galaxy. [ABSTRACT FROM AUTHOR]