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… 

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