相关论文: Frame-dragging and the kinematics of Galactic-Cent…
I report the discovery of a new effect of General Relativity which is important to understand very rapidly rotating (Kerr) black holes. The orbital velocity of a test particle is no longer a monotonic function of the orbit radius when the…
Based on published sources, we have created a kinematic database on 220 massive (>10 solar masses) young Galactic star systems located within <3 kpc of the Sun. Out of them, approximately 100 objects are spectroscopic binary and multiple…
We present new proper motion measurements and simultaneous orbital solutions for three newly identified (S0-16, S0-19, and S0-20) and four previously known (S0-1, S0-2, S0-4, and S0-5) stars at the Galactic Center. This analysis pinpoints…
We study analytically a gravitational lens due to a deformed star, which is modeled by using a monopole and a quadrupole moment. Positions of the images are discussed for a source on the principal axis. We present explicit expressions for…
The measurement of relativistic effects around the galactic center may allow in the near future to strongly constrain the parameters of the supermassive black hole likely present at the galactic center (Sgr A*). As a by-product of these…
We investigate the perihelion shift of the planetary motion and the bending of starlight in the Schwarzschild field modified by the presence of a $\Lambda$-term plus a conical defect. This analysis generalizes an earlier result obtained by…
The measurement of spin effects in general relativity has recently taken centre stage with the successfully launched Gravity Probe B experiment coming toward an end, coupled with recently reported measurements using laser ranging. Many…
We aim at a detailed description of the kinematic properties of the old, (several Gyrs) late-type CO-absorption star population among the Galactic centre (GC) cluster stars. We applied AO-assisted, near-infrared imaging and integral-field…
The gravitational lensing of relativistic neutral massive particles caused by a Kerr-Newman black hole is investigated systematically in the weak-field limit. Based on the Kerr-Newman metric in Boyer-Lindquist coordinates, we first derive…
We consider the slowly rotating relativistic stars with a uniform angular velocity in the scalar-tensor gravity, and examine the rotational effect around such compact objects. For this purpose, we derive a 2nd order differential equation…
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…
In this paper, we first investigate some aspects of frame dragging in strong gravity. The computations are carried out for the Kerr black hole and for the rotating Janis-Newman-Winicour solution, that is known to have a naked singularity on…
Satellite tracking involves sending electromagnetic signals to Earth. Both the orbit of the spacecraft and the electromagnetic signals themselves are affected by the curvature of spacetime. The arrival time of the pulses is compared to the…
Analogous to magnetism in electrodynamics, it is gravitomagnetism in relativistic gravity. Since gravity determines locally inertial frames, in general relativity (GR) and other relativistic theories of gravity, frame-dragging with source…
The Galactic disk is expected to be spatially, kinematically, and chemically clustered on many scales due to both star formation and non-axisymmetries in the Galactic potential. In this work we calculate the spatial and kinematic two-point…
Recent measurements, of the velocities of stars near the center of the Milky Way have provided the strongest evidence for the presence of a supermassive black hole in a galaxy, but the observational uncertainties poorly constrain many of…
Several stars orbit around a black hole candidate of mass $3.7\times 10^6$ M$_{\odot}$, in the region of the Galactic Center (GC). Looking for General Relativistic (GR) periastron shifts is limited by the existence of a stellar cluster…
We review the current state of dynamical modeling for galaxies in terms of being able to measure both the central black hole mass and stellar orbital structure. Both of these must be known adequately to measure either property. The current…
In this paper we develop a calculation code to account for the effects carried by fast rotation on the observed spectra of early-type stars. Stars are assumed to be in rigid rotation and the grid of plane-parallel model atmospheres used to…
As a consequence of Birkhoff's theorem, the exterior gravitational field of a spherically symmetric star or black hole is always given by the Schwarzschild metric. In contrast, the exterior gravitational field of a rotating (axisymmetric)…