Contributed Talk - Splinter Relativistic

Friday, 25 September 2020, 09:00   (virtual room J)

The Galactic Center black hole with GRAVITY

GRAVITY Collaboration
Max-Planck-Institut für extraterrestrische Physik

The Galactic Center offers the rare possibility to test general relativity in the so-far unexplored regime close to a massive black hole. We will present the main results from the last three years of GRAVITY observations in the Galactic Center: the detection of the Schwarzschild precession and the gravitational redshift in the orbit of the star S2, as well as the detection of orbital motions close to the last stable orbit during a flare. The GRAVITY instrument, which was developed specifically for the observations of the Galactic Center black hole and its orbiting stars, is now routinely achieving ~3 milli-arcsecond imaging interferometry with a sensitivity several hundred times better than previous instruments. Its astrometric precision of few ten micro arcseconds corresponds to only few Schwarzschild radii of Galactic Center massive black hole, which opens up the possibility to test the fundamentals of gravity all the way from the underlying equivalence principles, to considerations on new physics and their characteristic scales and strengths.