Poster abstract details

The ESA astrometric mission Gaia will be able to carry out general relativistic tests by means of both global and differential astrometric measurements. Global tests will be done through the full astrometric reconstruction of the celestial sphere, while the differential experiments will be implemented in the form of repeated Eddington-like measurements, i.e., comparing the evolution of relative distances in stellar fields observed in the vicinity of a giant planet like Jupiter or Saturn. Recent results in Crosta and Mignard, 2006 (Class. Quantum Grav. 23,4853-4871), based on simulated observations, states that Gaia can provide, for the first time, the measurement of the bending effect due to the quadrupole moment with a 3-sigma confidence level. New simulations of the differential experiment which utilize selected fields extracted from the GSCII data base and a realistic error model as function of stellar magnitude and stray-light profile, show (i) real stellar scenarios observed by Gaia to perform the experiment, (ii) ways to improve the ability of Gaia to detect the quadrupole light deflection by investigating the instrumental and observational details involved in an all-differential experiment (iii) how to test the dynamical gravitational background due to Jupiter.