Related papers: Stellar rotation as a new observable to test gener…
Menten, Reid, Eckart and Genzel (1997) accurately determined the position of Sgr A* on an infrared image, by aligning the infrared image with positions measured for SiO masers, associated with infrared-bright evolved stars, at radio…
We developed a numerical methodology to compute the fully-relativistic propagation time of photons emitted by a pulsar in orbit around a massive compact object, like the supermassive black hole Sagittarius A* in the Galactic Center, whose…
The Event Horizon Telescope (EHT), a global 230 GHz VLBI array, achieves an angular resolution of ${\approx} 20\,\mu{\rm as}$, sufficient to resolve the supermassive black hole Sagittarius A* (Sgr A*). This resolution may soon enable…
We present the results of 16 years of monitoring stellar orbits around the massive black hole in center of the Milky Way using high resolution NIR techniques. This work refines our previous analysis mainly by greatly improving the…
Submilliarcsecond astrometry and imaging of the black hole Sgr A* at the Galactic Center may become possible in the near future at infrared and submillimetre wavelengths. This resolution is sufficient to observe the silhouette the…
We study the overall spin precession frequency of a test gyroscope around a neutron star. The precession of the test gyroscope gives the signatures of the general relativistic effects that are present in the region of strong gravity of an…
Previous studies of the rotation law in the outer Galactic disc have mainly used gas tracers or clump giants. Here, we explore A and F stars as alternatives: these provide a much denser sampling in the outer disc than gas tracers and have…
We study the young S-stars within a distance of 0.04 pc from the supermassive black hole in the center of our Galaxy. Given how inhospitable the region is for star formation, their presence is more puzzling the younger we estimate their…
In the neighborhood of Sgr A*, several stars (S2, S12, S14, S1, S8, S13) enjoy an accurate determination of their orbital parameters. General Relativity predicts that the central black hole acts as a gravitational lens on these stars,…
Two groups of astronomers used the large telescopes Keck and VLT for decades to observe trajectories of bright stars near the Galactic Centre. Based on results of their observations the astronomers concluded that trajectories of the stars…
Sagittarius A*, the super-massive black hole at the center of the Milky Way, is surrounded by a small cluster of high velocity stars, known as the S-stars. We aim to constrain the amount and nature of stellar and dark mass associated with…
We study some possible observational signatures of $R^n$ gravity at Galactic scales and how these signatures could be used for constraining this type of $f(R)$ gravity. For that purpose, we performed two-body simulations in $R^n$ gravity…
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…
In a geocentric kinematically rotating ecliptical coordinate system in geodesic motion through the deformed spacetime of the Sun, both the longitude of the ascending node $\Omega$ and the inclination $I$ of an artificial satellite of the…
In two previous papers we presented the LARES 2 space experiment aimed at a very accurate test of frame-dragging and at other tests of fundamental physics and measurements of space geodesy and geodynamics. We presented the error sources of…
We perform a full analytical and numerical treatment, to the first post-Newtonian (1pN) order, of the general relativistic long-term spin precession of an orbiting gyroscope due to the mass quadrupole moment $J_2$ of its primary without any…
Stars orbiting within 1$\arcsec$ of the supermassive black hole in the Galactic Centre, Sgr A*, are notoriously difficult to detect due to obscuration by gas and dust. We show that some stars orbiting this region may be detectable via…
We present the results of a detailed kinematic analysis of a significant fraction of the known population of Galactic star clusters aimed at constraining the physical mechanisms driving the onset and evolution of cluster rotation. Our study…
We have developed a two-dimensional orbit averaged Fokker-Planck model of stellar clusters which expands on spherically symmetric one-dimensional models to include rotation and ellipticity. Physical effects such as collisions, finite…
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…