Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius A*

@article{Backer1999ProperMO,
  title={Proper Motion of the Compact, Nonthermal Radio Source in the Galactic Center, Sagittarius A*},
  author={Donald Charles Backer and Richard Anthony Sramek},
  journal={The Astrophysical Journal},
  year={1999},
  volume={524},
  pages={805-815}
}
Proper motions and radial velocities of luminous infrared stars in the Galactic center have provided strong evidence for a dark mass of 2.5 × 106 M☉ in the central 0.05 pc of the Galaxy. The leading hypothesis for this mass is a black hole. High angular resolution measurements at radio wavelengths find a compact radio source, Sagittarius (Sgr) A*, that is either the faint glow from a small amount of material accreting onto the hole with low radiative efficiency or a miniature active galactic… Expand

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References

SHOWING 1-10 OF 48 REFERENCES
Stellar proper motions in the central 0.1 PC of the galaxy
We report the first results of a programme to measure proper motions of stars in the innermost core of the Galaxy. From high-resolution near-infrared imaging over the last four years we haveExpand
The Proper Motion of Sagittarius A*. I. First VLBA Results
We observed Sgr A* and two extragalactic radio sources nearby in angle with the VLBA over a period of 2 yr and measured relative positions with an accuracy approaching 0.1 mas. The apparent properExpand
Advection-Dominated Accretion Model of Sagittarius A ∗ : Evidence for a Black Hole at the Galactic Center
Sagittarius A*, which is located at the Galactic center, is a puzzling source. It has a mass of M = (2.5 ± 0.4) × 106 M☉, which makes it an excellent black hole candidate. Observations of stellarExpand
High Proper-Motion Stars in the Vicinity of Sagittarius A*: Evidence for a Supermassive Black Hole at the Center of Our Galaxy
Over a 2 year period we have conducted a di†raction-limited imaging study at 2.2 km of the inner 6A ) 6A of the central stellar cluster of the Galaxy using the W. M. Keck 10 m telescope. The K-bandExpand
7 Millimeter VLBA Observations of Sagittarius A
We present 7 mm Very Long Baseline Array observations of the compact nonthermal radio source in the Galactic center, Sagittarius A*. These observations confirm the hypothesis that the image of Sgr A*Expand
Anisotropy in the angular broadening of Sagittarius A* at the Galactic center
We present the results of a lambda = 20 cm (VLA) squared observation of the compact Galactic center radio source Sgr A(*). The scatter-broadened image is elongated in the east-west direction, with anExpand
Radio Observations of Sgr A
Sgr A* is a unique radio source in the dynamical center of the galaxy. It has a spectrum that suggests a nonuniform distribution of synchrotron emitting particles and magnetic fields. Variations ofExpand
Explaining the spectrum of Sagittarius A* with a model of an accreting black hole
THE radio source at the centre of our Galaxy1, Sagittarius A* (Sgr A*), seems to be a low-luminosity version of active galactic nuclei—a massive black hole that is accreting gas from the surroundingExpand
Diameter and Proper Motion of SGR A
The best hypothesis for the energy source of the compact, nonthermal radio source in the center of our galaxy, Sagittarius A* (Sgr A*), is accretion onto a massive black hole from winds emanatingExpand
High-resolution VLBA imaging of the radio source Sgr A* at the Galactic Centre
THE compact non-thermal radio source at the Galactic Centre, known as Sgr A*, may mark the location of a massive black hole1,2. Here we present images of Sgr A* with milliarcsecond resolutionExpand
...
1
2
3
4
5
...