Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole

The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the last 2.7 decades we have monitored the star’s radial velocity and motion on the sky, mainly with the SINFONI and NACO adaptive optics (AO) instruments on the ESO VLT, and since 2017, with the four-telescope interferometric beam combiner instrument GRAVITY. In this Letter we report the first detection of the General Relativity (GR) Schwarzschild Precession (SP) in S2’s orbit. Owing to its highly elliptical orbit ( e = 0.88), S2’s SP is mainly a kink between the pre-and post-pericentre directions of motion ≈±1 year around pericentre passage, relative to…

• DF
  Deutsche Forschungsgemeinschaft
• BF
  Bundesministerium für Bildung und Forschung
• M
  Max-Planck-Gesellschaft
• CN
  Centre National de la Recherche Scientifique
• OD
  Observatoire de Paris, Université de Recherche Paris Sciences et Lettres
• FP
  Fundação para a Ciência e a Tecnologia

  Awards: SFRH/BSAB/142940/2018, UIDB/00099/2020