Related papers: Testing of General Relativity with Geodetic VLBI
A relativistic sub-picosecond model of gravitational time delay in radio astronomical observations is worked out and a new experimental test of general relativity is discussed in which the effect of retardation of gravity associated with…
We present a novel test of general relativity (GR): measuring the geometric component of the time delay due to gravitational lensing. GR predicts that photons and gravitational waves follow the same geodesic paths and thus experience the…
Light does not travel in a perfectly straight line when it passes near massive objects. In this work, we calculate the gravitational deflection of light using the gauge theory of unified gravity [Rep. Prog. Phys. 88, 057802 (2025)],…
VLBI astrometry allows coordinates of celestial radio sources to be determined with submilliarcsecond accuracy. In particular, with differential VLBI astrometry, the standard errors of relative positions and proper motions can be as small…
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…
We consider the gravity assist maneuver, that is, a correction of spacecraft motion at its passing near a planet, as a tool for evaluating the Eddington post-Newtonian parameters $\beta$ and $\gamma$, characterizing vacuum spherically…
Global Positioning System (GPS) satellites broadcast at frequencies of 1,575.42 MHz (L1) and of 1,227.60 MHz (L2). The dispersive property of the ionosphere can be used to combine independent measurements at the two frequencies to estimate…
The global astrometric observations of a GAIA-like satellite were modeled within the PPN formulation of Post-Newtonian gravitation. An extensive experimental campaign based on realistic end-to-end simulations was conducted to establish the…
Weyl gravity has been advanced in the recent past as an alternative to General Relativity (GR). The theory has had some success in fitting galactic rotation curves without the need for copious amounts of dark matter. To check the viability…
Recent theoretical works on alternative metric theories of gravity give greater significance to solar-system tests of General Relativity. In particular, it is suggested that the post-Newtonian parameter $\gamma$ ought to be determined with…
Gravitational lensing in metric theories of gravity is discussed. I introduce a generalized approximate metric element, inclusive of both post-post-Newtonian (ppN) contributions and gravito-magnetic field. Following Fermat's principle and…
Relativistic models of light propagation adopted for high-precision astrometry are based on the parametrised post-Newtonian formalism, which provides a framework for examining the effects of a hypothetical violation of general relativity on…
We demonstrate phase correction of 3 mm VLBI observations using the scanning 18 GHz to 26 GHz water vapour radiometer at Effelsberg and we demonstrate an absolute accuracy of 15 mm in zenith path delay by comparing with GPS and radiosondes.…
To evaluate a potential usually one analyzes trajectories of test particles. For the Galactic Center case astronomers use bright stars or photons, so there are two basic observational techniques to investigate a gravitational potential,…
The deflection of light ray passing near the Sun is calculated with quantum-corrected Newton's gravitation law. The satisfactory result suggests that there may exist other theoretical possibilities besides the theory of relativity.
Lorentz symmetry violations can be described by an effective field theory framework that contains both General Relativity and the Standard Model of particle physics called the Standard-Model extension (SME). Recently, post-fit analysis of…
The $ \gamma $-spacetime metric is a static and axially symmetric vacuum solution of the Einstein equation. This spacetime represents a naked singularity and it has an extra parameter $ \gamma $ which signifies deviations from spherical…
Extending geodetic and astrometric Very Long Baseline Interferometry (VLBI) observations from traditional centimeter wavebands to millimeter wavebands offers numerous scientific potentials and benefits. However, it was considered quite…
A relation between the photon mass, its frequency, $\nu$, and the deflection parameter, $\gamma$, determined by experimentalists (which characterizes the contribution of space curvature to gravitational deflection) is found. This amazing…
Einstein's theory of general relativity (GR) has been precisely tested on solar system scales, but extragalactic tests are still poorly performed. In this work, we use a newly compiled sample of galaxy-scale strong gravitational lenses to…