The Galactic Center as a gravitational laboratory

Riccardo Della Monica

University of Salamanca

The centre of the Milky Way has been subject of an intense observational program over the last thirty years, leading to exhibit the existence of a point source supermassive object named Sagittarius A (Sgr A). While stars orbiting around it are accelerated by gravity up to speeds of 10.000 km/s, Sgr A moves at less than 1 km/s. The kinematic properties of such stars, called S-stars, set up its mass to about 4 million solar masses, concentrated in a region of only six light hours. The study of the motion of these stars and the potential future discovery of pulsars orbiting Sgr A allows to probe the gravitational field of a supermassive black hole in a regime that had never been explored before. In this talk I will discuss the new avenue opened by such current and future observations to test alternative to the classical Schwarzschild black hole model.