相关论文: The Secular Aberration Drift and Future Challenges…

Finite eccentricities in mass-transferring eccentric binary systems can be explained by taking into account mass-loss and mass-transfer processes that often occur in these systems. These processes can be treated as perturbations to the…

The gravitational field of a massive object (for instance, of a galaxy group or cluster) disturbs the Hubble stream, decreasing its speed. Dependence $v(r_0)$ of the radial velocity of the stream from the present-day radius $r_0$ can be…

The highly-accurate optical reference frame GCRF (Gaia Celestial Reference Frame) is expected to be available in several years. By the same time, a new version of radio reference frame ICRF (International Celestial Reference Frame) will be…

Astrometry, the measurement of positions and motions of the stars, is one of the oldest disciplines in Astronomy, extending back at least as far as Hipparchus' discovery of the precession of Earth's axes in 190 BCE by comparing his catalog…

The last decade lead to major progress in asteroseismology and stellar physics with the advent of space missions. Thanks to the richness and precision of current oscillation spectra, sophisticated seismic probing techniques allow us now to…

We investigate the orbital evolution of a system of N mutually interacting stars on initially circular orbits around the dominating central mass. We include perturbative influence of a distant axisymmetric source and an extended spherical…

It is shown that the curvature of spacetime, a possible net electric charge on the sun, a small positive cosmological constant and the oblateness of the sun, in conjunction with solar radiation pressure (SPR), affect the bound orbital…

The Fermi satellite has recently detected gamma ray emission from the central regions of our Galaxy. This may be evidence for dark matter particles, a major component of the standard cosmological model, annihilating to produce high-energy…

Equations of light, propagating from quasar to observer on earth, are integrated in the time-dependent gravitational field of the solar system by making use of either retarded or advanced solutions of the Einstein field equations. This…

The subtle influence of gravitational waves on the apparent positioning of celestial bodies offers novel observational windows. We calculate the expected astrometric signal induced by an isotropic Stochastic Gravitational Wave Background…

According to the cosmological principle, the Universe should appear isotropic, without any preferred directions, to an observer whom we may consider to be fixed in the co-moving co-ordinate system of the expanding Universe. Such an observer…

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…

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…

In-spiraling supermassive black holes should emit gravitational waves, which would produce characteristic distortions in the time of arrival residuals from millisecond pulsars. Multiple national and regional consortia have constructed…

Deep surveys conducted during the past decades have shown that galaxies in the distant universe are generally of more irregular shapes, and are disky in appearance and in their star formation rate, compared to galaxies in similar…

Most galaxies closely follow the radial acceleration relation (RAR), which tightly links the observed accelerations to those predicted by Newtonian gravity from visible baryonic matter. Galaxy clusters, however, deviate from this relation.…

In this work we study how scalar fields may affect solar observables, and use the constraint on the Sun's central temperature to extract bounds on the parameters of relevant models. Also, a scalar field driven by a suitable potential is…

An intervening galaxy acts as a gravitational lens and produces multiple images of a single source such as a remote galaxy. Galaxies have peculiar speeds in addition to the bulk motion arising due to the expansion of the universe. There is…

Galaxies are gigantic physical systems having a typical size of many tens of thousands of light years. Thus any change at the center of the galaxy will affect the rim only tens of millennia later. Those retardation effects seems to be…

The eccentricity evolution of multiple planet systems can provide valuable constraints on planet formation models. Unfortunately, the inevitable uncertainties in the current orbital elements can lead to significant ambiguities in the nature…