相关论文: Apparent Deviations from Keplerian Acceleration fo…
The effect of stars on the lensing properties of the supermassive black hole in the Galactic Center is similar to the effect of planets on microlensing by a star. We show that the dense stellar cluster around SgrA* increases by factors of a…
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…
Measurements of stellar velocities and variable X-ray emission near the centre of the Milky Way have provided the strongest evidence so far that the dark mass concentrations seen in many galactic nuclei are likely supermassive black holes,…
The gravitational lensing of a finite star moving around a rotating Kerr black hole has been numerically calculated. Calculations for the direct image of the star and for the first and second light echoes have been performed for the star…
Accelerating black holes, connected to cosmic strings could evolve to supermassive black holes. However, if they are going to take part in structure formation and resides at the center of galaxies, their acceleration should be small. This…
The massive black hole at the Galactic center Sgr A* is surrounded by a cluster of stars orbiting around it. Light from these stars is bent by the gravitational field of the black hole, giving rise to several phenomena: astrometric…
We calculate the effects of frame dragging on the Galactic-Center stars. Assuming the stars are only slightly relativistic, we derive an approximation to the Kerr metric, which turns out to be a weak field Schwarzschild metric plus a frame…
We simulate the astrometric observations of stars moving close to the black hole in the Galactic Center. We show, that for orbits =<1000 AU and position measurements with the accuracy of the Keck Interferometer, the periastron motion of…
The Galactic Centre S-stars orbiting the central supermassive black hole reach velocities of a few percent of the speed of light. The GR-induced perturbations to the redshift enter the dynamics via two distinct channels. The post-Newtonian…
The spin and quadrupole moment of the supermassive black hole at the Galactic center can in principle be measured via astrometric monitoring of stars orbiting at milliparsec (mpc) distances, allowing tests of general relativistic "no-hair"…
Accelerating supermassive black holes, connected to cosmic strings, could contribute to structure formation and get captured by galaxies if their velocities are small. This would mean that the acceleration of these black holes is small too.…
In galactic nuclei, the gravitational potential is dominated by the central supermassive black hole, so stars follow quasi-Keplerian orbits. These orbits are distorted by gravitational forces from other stars, leading to long-term orbital…
Episodically accreting black holes are thought to produce flares when a chunk of particles is accelerated to high velocity near the black hole horizon. This also seems to be the case of Sagittarius A* in the Galactic Center, where the…
We identify a new secular instability of eccentric stellar disks around supermassive black holes. We show that retrograde precession of the stellar orbits, due to the presence of a stellar cusp, induces coherent torques that amplify…
The S-stars discovered in the Galactic center (GC) are expected to provide unique dynamical tests of the Kerr metric of the massive black hole (MBH) orbited by them. In order to obtain unbiased measurements of its spin and the related…
Supermassive black holes in the centre of galaxies dominate the gravitational potential of their surrounding stellar clusters. In these dense environments, stars follow nearly Keplerian orbits, which get slowly distorted as a result of the…
We investigate the ability of the Laser Interferometer Space Antenna (LISA) to measure the center of mass acceleration of stellar-origin black hole binaries emitting gravitational waves. Our analysis is based on the idea that the…
Objects falling into an overdensity appear larger on its near side and smaller on its far side than other objects at the same redshift. This produces a dipolar pattern of magnification, primarily as a consequence of the Doppler effect. At…
We consider the time derivatives of the period $P$ of pulsars at the Galactic Center due to variations in their orbital Doppler shifts. We show that in conjunction with a measurement of a pulsar's proper motion and its projected separation…
We discuss experiments achievable via monitoring of stellar dynamics near the massive black hole at the Galactic center with a next generation, extremely large telescope (ELT). Given the likely observational capabilities of an ELT and…