Gravitational lens model of the double QSO 0957 + 561 A,B incorporating VLBI features

Abstract

The twin quasar QSO 0957 + 561 A,B along with bright radio arches and VLBI structures is modeled using a gravitational lens consisting of the giant elliptical galaxy and the background cluster. The effective time-delay between components A and B comes out to be around one year, which is significantly different from the value obtained by Young et al. for a similar set of lens parameters. It is demonstrated that the observed intensity variation in component B between 1979 and mid-1981, reported by Keel (1982) can result from minilensing by low mass stars.