Related papers: Testing of General Relativity with Geodetic VLBI
Results of VLBI and GPS observations were analyzed with goal to investigate differences in observed baseline length derived from both techniques. VLBI coordinates for European stations were obtained from processing of all available…
The accuracy reached in the past few years by Satellite Laser Ranging (SLR) allows for measuring even tiny features of the Earth's gravitational field predicted by Einstein's General Relativity by means of artificial satellites. The…
Almost all of the studies devoted to relativistic astrometry are based on the integration of the null geodesic differential equations. However, the gravitational deflection of light rays can be calculated by a different method, based on the…
As an extension of our previous paper, instead of the total deflection angle $\alpha$, we will mainly focus on discussing the measurable angle of the light ray $\psi$ at the position of the observer in Kerr--de Sitter spacetime which…
A key task in cosmology is to test the validity of general relativity (GR) at cosmological scales and, therefore, to distinguish between dark energy and modified gravity (MG) as the driver of the late-time cosmic acceleration. The decay…
We propose an alternative method to detect the secular aberration drift induced by the solar system acceleration due to the attraction to the Galaxy centre. This method is free of the individual radio source proper motion caused by…
We report the results of a successful 12 hour 22 GHz VLBI experiment using a heterogeneous network that includes radio telescopes of the Long Baseline Array (LBA) in Australia and several VLBI stations that regularly observe in geodetic…
A simple general relativity theory for objects moving in gravitational fields is developed based on studying the behavior of an atom in a gravitational field. The theory is applied to calculate the satellite time dilation, light deflection…
Very Long Baseline Interferometry (VLBI) at radio wavelengths can provide astrometry accurate to 10 micro-arcseconds or better (i.e. better than the target GAIA accuracy) without being limited by dust obscuration. This means that unlike…
In this paper we present new observations of the gravitational lens system JVAS B0218+357 made with a global VLBI network at a frequency of 8.4 GHz. Our maps have an rms noise of 30 microJy/beam and with these we have been able to image…
Recent experiments have successfully tested Einstein's general theory of relativity to remarkable precision. We discuss recent progress in the tests of relativistic gravity in the solar system and present motivations for the new generation…
We illustrate a method for estimating the vertical position of the Sun above the Galactic plane by $\gamma$-ray observations. Photons of $\gamma$-ray wavelengths are particularly well suited for geometrical and kinematic studies of the…
Summarizes current status of radio interferometry at radio frequencies between Earth-based receivers, for astrometric and geodetic applications. Emphasizes theoretical models of VLBI observables that are required to extract results at the…
Radio observations using the Very Long Baseline Interferometry (VLBI) technique typically have fields of view of only a few arcseconds, due to the computational problems inherent in imaging larger fields. Furthermore, sensitivity…
Strong gravitational lensing effect is a powerful tool to probe cosmological models and gravity theories. Recently, the time-delay cosmography from strong lensing and the stellar kinematics of the deflector, which encode the Hubble constant…
The alignment between the radio-based International Celestial Reference Frame (ICRF) and the optical Gaia Celestial Reference Frame (Gaia-CRF) is critical for multi-waveband astronomy, yet systematic offsets at the optical bright end (G<13)…
A possible deviation from the precession of the Gravity Probe-B gyroscope predicted by general relativity is obtained in the nonsymmetric gravity theory. The time delay of radio signals emitted by spacecraft at planetary distances from the…
This work arose as an aftermath of Cassini's 2002 experiment \cite{bblipt03}, in which the PPN parameter $\gamma$ was measured with an accuracy $\sigma_\gamma = 2.3\times 10^{-5}$ and found consistent with the prediction $\gamma =1$ of…
In this proceeding, we show how observations of Solar System Objects with Gaia can be used to test General Relativity and to constrain modified gravitational theories. The high number of Solar System objects observed and the variety of…
Optical Very Long Baseline Interferometry (VLBI) offers the potential for unprecedented angular resolution in both astronomical imaging and precision measurements. Classical approaches, however, face significant limitations due to photon…