相关论文: Clocks around Sgr A*

Precise measurements of the S-stars orbiting SgrA* have set strong constraints on the nature of the compact object at the centre of the Milky Way. The presence of a black hole in that region is well established, but its neighboring…

Observations of the precessing orbits of stars very near the massive black hole in the galactic center could provide measurements of the spin and quadrupole moment of the hole and thereby test the no-hair theorem of general relativity.…

The discovery of radio pulsars in compact orbits around Sgr A* would allow an unprecedented and detailed investigation of the spacetime of the supermassive black hole. This paper shows that pulsar timing, including that of a single pulsar,…

Timing a pulsar orbiting around Sagittarius A* (Sgr A*) can provide us with a unique opportunity of testing gravity theories. We investigate the detectability of a vector charge carried by the Sgr A* black hole (BH) in the bumblebee gravity…

We analyze the orbital dynamics of spherical test bodies in ``black hole surrounded by dark matter halo'' spherically symmetric spacetimes. When the test body pulsates periodically (such as a variable star), altering its quadrupole tensor,…

Radio timing observations of a millisecond pulsar in orbit around the Galactic centre black hole (BH) or a BH at the centre of globular clusters could answer foundational questions in astrophysics and fundamental physics. Pulsar radio…

We investigate the geodesic motions of timelike particles around a static hairy black hole with conformally coupled scalar field. We mainly focus on the effects of the scalar charge and electric charge on the marginally bound orbits (MBO),…

We consider the orbital evolution of the S-stars, the young main-sequence stars near the supermassive black hole (SBH) at the Galactic center (GC), and put constraints on competing models for their origin. Our analysis includes for the…

The Galactic center is an ideal laboratory to study strong-field general relativistic phenomena, as the supermassive black hole Sgr A* has the biggest angular Schwarzschild radius among all black holes. This article presents three different…

A rotating black hole causes the spin-axis of a nearby pulsar to precess due to geodetic and gravitomagnetic frame-dragging effects. The aim of our theoretical work here is to explore how this spin-precession can modify the rate at which…

The center of the Milky Way hosts the closest supermassive black hole, SgrA$^*$. Decades of near-infrared observations of our Galactic Center have shown the presence of a small population of stars (the so called S-star cluster) orbiting…

Stars closely approaching the massive black hole in the center of the Galaxy provide a unique opportunity to probe post-Newtonian physics in a yet unexplored regime of celestial mechanics. Recent advances in infrared stellar spectroscopy…

The star S2 orbiting the compact radio source Sgr A* is a precision probe of the gravitational field around the closest massive black hole (candidate). Over the last 2.7 decades we have monitored the star's radial velocity and motion on the…

Pulsars are rapidly rotating neutron stars emitting intense electromagnetic radiation that is detected on Earth as regular and precisely timed pulses. By exploiting their extreme regularity and comparing the real arrival times with a…

Studies of the inner few parsecs at the Galactic Centre provide evidence of a supermassive black hole, associated with the unusual, variable radio and infrared source Sgr A*. Our major aim is the study and analysis of the physical processes…

Recently, some S-stars (S4711, S62, S4714) orbiting the supermassive black hole (SMBH) in Sgr A$^\ast$ with short orbital periods ($7.6\,\mathrm{yr}\leq P_\mathrm{b}\leq 12\,\mathrm{yr}$) were discovered. It was suggested that they may be…

We show that the time-dependent Doppler effect should induce measureable deviations of the time history of the projected orbit of a star around the supermassive black hole in the Galactic center (SgrA*) from the expected Keplerian history.…

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…

In the past three decades, many stars orbiting about the supermassive black hole (SMBH) at the Galactic Centre (Sgr A*) were identified. Their orbital nature can give stringent constraints for the mass of the SMBH. In particular, the star…

Recent measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a 3.6-million-solar-mass black hole. Sgr A* is remarkably faint in all wavebands other than the radio…