Stars lensed by the Supermassive Black Hole in the center of the Milky Way: predictions for future high-resolution instruments

Gravitational lensing is an important prediction of general relativity, providing both its test and a tool to detect faint but amplified sources and to measure masses of lenses. For some applications, (e.g., testing the theory), a point source lensed by a point-like lens would be more advantageous. However, until now only one gravitationally lensed star has been resolved. Future telescopes will resolve very small lensing signatures for stars orbiting the supermassive black hole (SMBH) in the center of the Milky Way. The lensing signatures, however, should be easier to detect for background stars. I will show the prediction that the Extremely Large Telescope (ELT), Thirty Meter Telescope (TMT), and Giant Magellan Telescope (GMT) will resolve the lensed images of around 100 stars in the background of the SMBH. The James Webb Space Telescope (JWST) will likely be limited by the confusion caused by stars near the Galactic center. I will also describe what observational characteristics are needed to achieve this (resolution and depth). Finally, I will discuss other observational signatures of lensed stars, which could be searched for with high-resolution instruments.