Structure of Sagittarius A* at 86 GHz using VLBI Closure Quantities

@article{Doeleman2001StructureOS,
  title={Structure of Sagittarius A* at 86 GHz using VLBI Closure Quantities},
  author={Sheperd S. Doeleman and Z.-Q. Shen and Alan E. E. Rogers and Geoffrey C. Bower and Melvyn C. H. Wright and J. H. Zhao and Donald Charles Backer and Joseph W. Crowley and Robert W. Freund and Paul T. P. Ho and K. Y. Lo and David P. Woody},
  journal={The Astronomical Journal},
  year={2001},
  volume={121},
  pages={2610 - 2617}
}
At radio wavelengths, images of the compact radio source Sagittarius A* (Sgr A*) in the Galactic center are scatter broadened with a λ2 dependence due to an intervening ionized medium. We present VLBI observations of Sgr A* at 86 GHz using a six station array, including the VLBA antennas at Pie Town, Fort Davis, and Los Alamos, the 12 m antenna at Kitt Peak, and the millimeter arrays at Hat Creek and Owens Valley. To avoid systematic errors due to imperfect antenna calibration, the data were… 

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References

SHOWING 1-10 OF 31 REFERENCES

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*

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 proper

Radio structure at 8.4 GHz in Sagittarius A, the compact radio source at the Galactic center

VLBI observations of the compact, nonthermal radio source at the Galactic center show it to be elongated at 8.4 GHz along a position angle of 82 + or - 6 deg. The source has an axial ratio of 0.53 +

Intrinsic Size of Sagittarius A*: 72 Schwarzschild Radii

Recent proper motion studies of stars at the very center of the Galaxy strongly suggest that Sagittarius A*, the compact nonthermal radio source at the Galactic center, is a 2.5×106 M☉ black hole. By

Upper Limit of 3.3 Astronomical Units to the Diameter of the Galactic Center Radio Source Sgr A*

In observations at long wavelengths, the apparent angular size of Sgr A* decreases in the manner expected for emission from a point source scattered by electron density fluctuations along the line of sight, which is consistent with an extrapolation from results at longer wavelengths.

Anisotropic Radio Scattering of NGC 6334B

The extragalactic radio source NGC 6334B is the most strongly scattered object known, with an angular size of 3'' at 20 cm wavelength. Its angular size scales as the square of the observing

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

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

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 diffraction-limited imaging study at 2.2 μm of the inner 6'' × 6'' of the central stellar cluster of the Galaxy using the W. M. Keck 10 m telescope. The

An accreting black hole model for sagittarius A

Several observations, notably of broad He I, Br-alpha, and Br-gamma emission lines from the vicinity of IRS 16, indicate the presence of a strong circumnuclear wind near the dynamical center of the

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 surrounding