Gravitational Lensing of stars orbiting Sgr A

摘要

There are many indications that the center of our Galaxy hosts a supermassive black hole, corresponding to the radio source Sgr A*. Thanks to the observations in the near infrared band, it has been possible to determine the orbits of several stars moving in the neighborhood of the Galactic center. General Relativity tells us that the central black hole, acting as a gravitational lens, bends the light rays of these source stars. As a consequence of this fact, a secondary image and two infinite series of relativistic images will be generated. In the framework of Schwarzschild black hole, we have calculated the light curves for the secondary and the first two relativistic images for each star examined. In this way, we have been able to estimate the best times to observe the secondary images, which will happen when the stars approach the minimum distance from the black hole.