Orbital precession of stars in the Galactic center

Abstract

The region around the center of our Galaxy is very dense of stars. The kinematics of inner moving stars in the Galaxy (the so called S-stars) has been deeply studied by different research groups leading to the conclusion of the existence of a very compact object (Sgr A${}^{\ast }$, likely a supermassive black hole) responsible for their high speed. Here we start from the observational evidence of orbital apsidal line precession for the S2 (also called S0-2) star to investigate on a theoretical side what level of quality in such regime of relatively strong gravitational field is reached in the orbit angular precession determination when using a direct orbital integration of the star motion subjected to an acceleration computed in the post-Newtonian (PN) scheme up to different orders. This approach, although approximated and limited to particle speed not exceeding $\sim 0.3c$, allows the inclusion of various effects, like that of a possible spin of the central massive object. Our results show that the inclusion of PN terms above the standard 1PN term (the one corresponding to the classic Einstein-Schwarzschild estimate of pericenter advance) is compulsory to determine angular precession at sufficient level of accuracy for those penetrating stars that would allow to pick contemporary the value of the mass and of the spin of a rotating (Kerr-like) super massive black hole (SMBH). We discuss how future observational data, together with a proper modelization, could allow the determination of both mass and spin of the SMBH of our Galaxy.

12 pages, 8 figures, 7 tables. Submitted to Monthly Notices of the Royal Astronomical Society

References in corpus (7)

• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• Testing the general relativistic ''no-hair'' theorems using the galactic center black hole SgrA*
• Twelve years of spectroscopic monitoring in the Galactic Center: the closest look at S-stars near the black hole
• Dynamics of compact objects clusters: A post-Newtonian study
• Spectroscopic Detection of a Cusp of Late-type Stars around the Central Black Hole in the Milky Way
• Dynamics of a Superdense Cluster of Black Holes and the Formation of the Galactic SMBH
• On the 2PN pericentre precession in the general theory of relativity and the recently discovered fast orbiting S-stars in Sgr A${}^{\ast }$

Cited by in corpus (3)

• Improving constraints on the extended mass distribution in the Galactic Center with stellar orbits
• Dark Matter reconstruction from stellar orbits in the Galactic Centre
• Impact of a granular mass distribution on the orbit of S2 in the Galactic center