scholarly journals Mass distribution in the Galactic Center based on interferometric astrometry of multiple stellar orbits

2021 ◽  
Author(s):  
◽  
R. Abuter ◽  
N. Aimar ◽  
A. Amorim ◽  
J. Ball ◽  
...  
Keyword(s):  
Mass Distribution ◽  
Galactic Center ◽  
Stellar Orbits

scholarly journals 15 years of high precision astrometry in the Galactic Center

2007 ◽  
Vol 3 (S248) ◽  
pp. 466-469
Author(s):  
S. Gillessen ◽  
R. Genzel ◽  
F. Eisenhauer ◽  
T. Ott ◽  
S. Trippe ◽  
...  
Keyword(s):  
Black Hole ◽  
Mass Distribution ◽  
Near Infrared ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Data Set ◽  
Stellar Orbits ◽  
Supermassive Black Hole ◽  
Near Future ◽  
Precision Astrometry

AbstractIn 1992, we obtained the first observations of S2 a star close to the supermassive black hole at the Galactic Center. In 2002, S2 passed its periastron and in 2007, it completed a first fully observed revolution. This orbit allowed us to determine the mass of and the distance to the supermassive black hole with unprecedented accuracy. Here we present a re-analysis of the data set, enhancing the astrometric accuracy to 0.5 mas and increasing the number of well-determined stellar orbits to roughly 15. This allows to constrain the extended mass distribution around the massive black hole and will lead in the near future to the detection of post-Newtonian effects. We will also give an outlook on the potential of interferometric near-infrared astrometry with 10 microarcsecond accuracy from the VLTI.

scholarly journals MONITORING STELLAR ORBITS AROUND THE MASSIVE BLACK HOLE IN THE GALACTIC CENTER

2009 ◽  
Vol 692 (2) ◽  
pp. 1075-1109 ◽  
Author(s):  
S. Gillessen ◽  
F. Eisenhauer ◽  
S. Trippe ◽  
T. Alexander ◽  
R. Genzel ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Massive Black Hole ◽  
Stellar Orbits

scholarly journals Testing the black hole no-hair theorem with Galactic Center stellar orbits

2021 ◽  
Vol 103 (8) ◽  
Author(s):  
Hong Qi ◽  
Richard O’Shaughnessy ◽  
Patrick Brady
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Stellar Orbits

scholarly journals Gas Feeding Toward the Central Neutral Ring in the Galactic Center

1989 ◽  
Vol 136 ◽  
pp. 379-382
Author(s):  
P. T. P. Ho ◽  
J. M. Jackson ◽  
J. T. Armstrong ◽  
J. C. Szczepanski
Keyword(s):  
Mass Distribution ◽  
Millimeter Wave ◽  
Gas Flow ◽  
Galactic Center ◽  
Ammonia Emission ◽  
Nuclear Region ◽  
Ionized Gas ◽  
Brightness Temperatures ◽  
Dominant Feature ◽  
Size Scales

VLA observations in the (J, K)=(3,3) line of ammonia reveal new structures in the Galactic center region. An approximate ring of emission is centered on the central ionized streamers. This ring, seen previously in millimeter-wave interferometer maps, is very clumpy in the ammonia emission, with size scales ≲10″ (0.4 pc). The clumps show good spatial and velocity agreement with the ionized gas, and are warm with brightness temperatures exceeding 30 K. A comparison of the (3,3) to (1,1) ratio indicates considerably higher gas temperatures. This circumnuclear ring may not be the dominant feature in the mass distribution of the circumnuclear gas. A streamer, immediately to the south of the Galactic center, connects the gas complex at lII= −4′ (~10 pc) directly to the Galactic center. This streamer may define the path for gas flow into the nuclear region.

scholarly journals Periastron shifts of stellar orbits near the Galactic Center

2001 ◽  
Vol 374 (1) ◽  
pp. 95-104 ◽  
Author(s):  
G. F. Rubilar ◽  
A. Eckart
Keyword(s):  
Galactic Center ◽  
Stellar Orbits

scholarly journals Testing properties of the Galactic center black hole using stellar orbits

2010 ◽  
Vol 81 (6) ◽  
Author(s):  
David Merritt ◽  
Tal Alexander ◽  
Seppo Mikkola ◽  
Clifford M. Will
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Stellar Orbits

scholarly journals Microlensing by Free-Floating Brown Dwarfs

2003 ◽  
Vol 211 ◽  
pp. 509-514
Author(s):  
Hans Zinnecker
Keyword(s):  
Optical Depth ◽  
Mass Distribution ◽  
Surface Density ◽  
Near Infrared ◽  
Galactic Center ◽  
Brown Dwarfs ◽  
Wide Field ◽  
Full Width

We propose a near-infrared microlensing survey of the central 2 degree field of the Galactic Center, in an attempt to estimate the surface density and mass distribution of distant free-floating brown dwarfs in the bulge and in the disk, acting as lenses of bright stars towards the Galactic Center. We estimate the probability (optical depth) of microlensing events to be 10-7 and the typical timescale (full-width) of the amplification lightcurve to be about 1 week. The necessary wide-field NIR survey technology should soon be available on UKIRT, CFHT, and with VISTA at ESO/Paranal.

scholarly journals 6.5. Hydrodynamical simulations as probes for the structure of the galactic center

1998 ◽  
Vol 184 ◽  
pp. 271-272
Author(s):  
K. Wada ◽  
T. Minezaki ◽  
K. Sakamoto ◽  
H. Fukuda
Keyword(s):  
Numerical Modeling ◽  
Numerical Simulations ◽  
Mass Distribution ◽  
Galactic Center ◽  
Dynamical Behavior ◽  
Interstellar Gas ◽  
Interstellar Gas In Galaxies ◽  
Dynamical Parameters ◽  
Pattern Speed ◽  
Hydrodynamical Simulations

Numerical modeling of the interstellar gas in galaxies is an effective approach to infer galactic gravitational structure. This is because the dynamical behavior of gas is very sensitive to the background gravitational potential. Since the dynamical resonances depend closely on the mass distribution and the pattern speed of the non-axisymmetric component, it is possible to determine these dynamical parameters by comparison of numerical simulations and gas observations.

scholarly journals The distance to the Galactic Center

2012 ◽  
Vol 8 (S289) ◽  
pp. 29-35 ◽  
Author(s):  
Stefan Gillessen ◽  
Frank Eisenhauer ◽  
Tobias K. Fritz ◽  
Oliver Pfuhl ◽  
Thomas Ott ◽  
...  
Keyword(s):  
Black Hole ◽  
Galactic Center ◽  
Distance Estimate ◽  
Massive Black Hole ◽  
Geometric Distance ◽  
Stellar Orbits ◽  
Fundamental Parameters ◽  
The Galaxy ◽  
Error Bars ◽  
Definition Of

AbstractOne of the Milky Way's fundamental parameters is the distance of the Sun from the Galactic Center, R0. This article reviews the various ways of estimating R0, placing special emphasis on methods that have become possible recently. In particular, we focus on the geometric distance estimate made possible thanks to observations of individual stellar orbits around the massive black hole at the center of the Galaxy. The specific issues of concern there are the degeneracies with other parameters, most importantly the mass of the black hole and the definition of the reference frame. The current uncertainty is nevertheless only a few percent, with error bars shrinking every year.

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