Related papers: Stellar Orbits Around the Galactic Center Black Ho…

The nature of the massive object at the Galactic Center (Sgr A$^{*}$) is still unclear even if various observational campaigns led many authors to believe that our Galaxy hosts a super-massive black hole with mass $M\simeq 2.6\times 10^6$…

We show that at any given time, the Galactocentric black hole Sgr A* is expected to be microlensing N(lens)=1.7 bulge stars if the threshold of detectability of the fainter image is K(thr)=21, and about N(lens)=8 sources if K(thr)=23. The…

ALMA observations of the Galactic center with spatial resolution $2.61"\times0.97"$ resulted in the detection of 11 SiO (5-4) clumps of molecular gas within 0.6pc (15$"$) of Sgr A*, interior to the 2-pc circumnuclear molecular ring. The…

Most galactic nuclei are now believed to harbour supermassive black holes. Studies of stellar motions in the central few light-years of our Milky Way Galaxy indicate the presence of a dark object with a mass of about 2.6 million solar…

We estimate the mass of the central black hole in our Galaxy from stellar kinematical data published by Ghez et al. (1998) and Genzel et al. (2000). For this we develop a method, related to Merritt (1993), for non-parametrically…

We describe a quasi-equilibrium profile of dark matter particles in the inner parsec of the Galaxy, rho ~ r^-3/2. This "mini-cusp" profile is caused by scattering with the dense stellar cluster around the supermassive black hole in Sgr A*…

Measurements of stellar orbits provide compelling evidence that the compact radio source Sagittarius A* at the Galactic Centre is a black hole four million times the mass of the Sun. With the exception of modest X-ray and infrared flares,…

Stellar orbits at the Galactic Center provide a very clean probe of the gravitational potential of the supermassive black hole. They can be studied with unique precision, beyond the confusion limit of a single telescope, with the…

We report measurements with the VLBA of the position of Sgr A* with respect to two extragalactic radio sources over a period of eight years. The apparent proper motion of \sgrab relative to J1745-283 is 6.379 +/- 0.024 mas/y along a…

We measure the proper motion of the pulsar PSR J1745-2900 relative to the Galactic Center massive black hole, Sgr A*, using the Very Long Baseline Array (VLBA). The pulsar has a transverse velocity of 236 +/- 11 km s^-1 at position angle 22…

The Milky Way centre hosts a supermassive Black Hole (BH) with a mass of ~4*10^6 M_Sun. Sgr A*, its electromagnetic counterpart, currently appears as an extremely weak source with a luminosity L~10^-9 L_Edd. The lowest known Eddington ratio…

If the stellar population of the bulge contains black holes formed in the final core collapse of ordinary stars with M \ga 30 M_{\odot}, then about 25,000 stellar mass black holes should have migrated by dynamical friction into the central…

We present new proper motions from the 10 m Keck telescopes for a puzzling population of massive, young stars located within 3.5" (0.14 pc) of the supermassive black hole at the Galactic Center. Our proper motion measurements have…

We discuss experiments achievable via monitoring of stellar dynamics near the massive black hole at the Galactic center with a next generation, extremely large telescope (ELT). Given the likely observational capabilities of an ELT and…

The centre of the Milky Way is occupied by a nuclear star cluster, which contains the supermassive black hole Sgr A*. The cluster is embedded in the larger surrounding nuclear stellar disc. These three components dominate the mass budget of…

A massive black hole resides in the center of most, perhaps all galaxies. The one in the center of our home galaxy, the Milky Way, provides a uniquely accessible laboratory for studying in detail the connections and interactions between a…

Information about the X-ray luminosity of the supermassive black hole located at the Galactic center (GC), Sgr A*, and its temporal variations in the past is imprinted in the scattered emission observed today in the direction towards giant…

A supermassive black hole SgrA* with the mass ~4x10^6 Msun resides at the centre of our galaxy. Building up such a massive black hole within the ~10^10 year lifetime of our galaxy would require a mean accretion rate of ~4x10^-4 Msun/yr. At…

Proper motion studies of stars in the centre of the Milky Way have been typically limited to the Arches and Quintuplet clusters and to the central parsec. Here, we present the first results of a large-scale proper motion study of stars…

The Galactic Center is the closest galactic nucleus that can be studied with unprecedented angular resolution and sensitivity. We summarize recent basic observational results on Sagittarius A* and the conditions for star formation in the…