Investigating the Relativistic Motion of the Stars Near the Supermassive Black Hole in the Galactic Center

Abstract

The S-star cluster in the Galactic center allows us to study the physics close to a supermassive black hole, including distinctive dynamical tests of general relativity. Our best estimates for the mass of and the distance to Sgr A* using the three stars with the shortest period (S2, S38, and S55/S0-102) and Newtonian models are M_BH = (4.15+- 0.13 +- 0.57) x 10^6 M_sun and R_0 = 8.19 +- 0.11 +- 0.34 kpc. Additionally, we aim at a new and practical method to investigate the relativistic orbits of stars in the gravitational field near Sgr A*. We use a first-order post- Newtonian approximation to calculate the stellar orbits with a broad range of periapse distance r_p. We present a method that employs the changes in orbital elements derived from elliptical fits to different sections of the orbit. These changes are correlated with the relativistic parameter defined as Υ = r_s/r_p (with r_s being the Schwarzschild radius) and can be used to derive Υ from observational data. For S2 we find a value of Υ = 0.00088 +- 0.00080, which is consistent, within the uncertainty, with the expected value of Υ = 0.00065 derived from MBH and the orbit of S2. We argue that the derived quantity is unlikely to be dominated by perturbing influences such as noise on the derived stellar positions, field rotation, and drifts in black hole mass.

27 pages, 24 figures

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Cited by in corpus (19)

• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• Supermassive black holes as possible sources of ultra high energy cosmic rays
• S62 and S4711: Indications of a population of faint fast moving stars inside the S2 orbit -- S4711 on a 7.6 year orbit around Sgr~A*
• General relativistic effects on the orbit of the S2 star with GRAVITY
• S62 on a 9.9 yr Orbit around SgrA*
• Fifty years of energy extraction from rotating black hole: revisiting magnetic Penrose process
• Kinematic Structure of the Galactic Center S-cluster
• The dark mass signature in the orbit of S2
• Towards an observational test of black hole versus naked singularity at the galactic center
• Monitoring dusty sources in the vicinity of Sgr A*
• Near- and mid-infrared observations in the inner tenth of a parsec of the Galactic center -- Detection of proper motion of a filament very close to Sgr~A*
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• First results from a large-scale proper motion study of the Galactic Centre
• A Significant Feature in the General Relativistic Time Evolution of the Redshift of Photons Coming from a Star Orbiting Sgr A*
• The apparent tail of the Galactic center object G2/DSO
• First observed interaction of the circumstellar envelope of an S-star with the environment of Sgr A*
• Observation of the apoapsis of S62 in 2019 with NIRC2 and SINFONI
• Kerr-Newman black hole lensing of relativistic massive particles in the weak field limit
• Possible evidence from the flaring activity of Sgr A* for a star at a distance of ~3.3 Schwarzscild radii from the blackhole