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The simultaneous spectrum of Sgr A* from 20cm to 1mm and the nature of the mm-excess

Heino Falcke·W. M. Goss·Hiroshi Matsuo·Peter Teuben·Jun-Hui Zhao·Robert Zylka
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Abstract

We report results from a multiwavelength campaign to measure the simultaneous spectrum of the super-massive black hole candidate Sgr A* in the Galactic Center from cm to mm-wavelengths using the VLA, BIMA, the Nobeyama 45m, and the IRAM 30m telescopes. The observations confirm that the previously detected mm-excess is an intrinsic feature of the spectrum of Sgr A*. The excess can be interpreted as due to the presence of an ultra-compact component of relativistic plasma with a size of a few Schwarzschild radii near the black hole. If so, Sgr A* might offer the unique possibility to image the putative black hole against the background of this component with future mm-VLBI experiments.

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Heino Falcke, W. M. Goss, Hiroshi Matsuo, Peter Teuben, Jun-Hui Zhao, Robert Zylka. 1998-01-12. The simultaneous spectrum of Sgr A* from 20cm to 1mm and the nature of the mm-excess. https://doi.org/10.1086/305687

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