Large scale evolution of the jets of GRS 1758-258: instabilities or precession?

GRS 1758–258 in the vicinity of the Galaxy center is one of the prototypes of microquasar. Radio observations revealed in the past a morphological evolution at large scales that have been attributed to the developing of instabilities. But precession could be at work as in other microquasars such as SS433 and 1E1740.7-2942. We used new and archival data to fit a precession model whose parameters let us find contraints on the physical properties and jet precession mechanisms in GRS 1758-258, in particular tidal torque induced by the secondary and Lense-Thirring effect. The results confirm that precession could be the responsible for the 18.48 day period actually assumed to be orbital, while a ~1 day orbital period seems more suitable in this system. However, precession could not be behind the large-scale behaviour of GRS 1758-258 jets, but the growth of instabilities. Taking all these things together, a new scenario is proposed for this microquasar.