Viewing the Shadow of the Black Hole at the Galactic Center

@article{Falcke1999ViewingTS,
  title={Viewing the Shadow of the Black Hole at the Galactic Center},
  author={Heino Falcke and Fulvio Melia and Eric Agol},
  journal={The Astrophysical Journal Letters},
  year={1999},
  volume={528},
  pages={L13 - L16}
}
In recent years, evidence for the existence of an ultracompact concentration of dark mass associated with the radio source Sagittarius A* in the Galactic center has become very strong. However, unambiguous proof that this object is indeed a black hole is still lacking. A defining characteristic of a black hole is the event horizon. To a distant observer, the event horizon casts a relatively large "shadow" with an apparent diameter of ∼10 gravitational radii that is due to the bending of light… 

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