The trajectory of a remote object image brightness center (IC) due to gravitational light deflection by stars of a foreground galaxy is studied. Typical shifts of the IC are of the order of 1- 10 microarcseconds. The trajectory depends strongly upon finite size of a (gaussian) source; in particular, it has a three-leaf form in case of moving Chang-Refsdal lens with point gravitator crossing the unperturbed object image. The simulations of image shifts in case of equal velocity of gravitators have been carried out for large optical depth with external shear; their statistics allows to determine the shear parameters.
19th Texas Symposium on Relativistic Astrophysics and Cosmology
- Pub Date:
- December 1998