Falcke et al./Sgr A* Spectrum

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

H. Falcke1,2, W.M. Goss3, H. Matsuo4, P. Teuben1, J.-H. Zhao5, R. Zylka6

1Department of Astronomy, University of Maryland, College Park, MD 20742-2421, USA (hfalcke, teuben@astro.umd.edu)
2Current Address: Max-Planck-Institut für Radioastronomie, Auf den Hüugel 69, D-53121 Bonn, Germany (hfalcke@mpifr-bonn.mpg.de)
3NRAO, P.O. Box O, Socorro, NM 87801-0387 (mgoss@nrao.edu)
4Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-13, Japan (matsuo@nro.nao.ac.jp)
5Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (jzhao@cfa.harvard.edu)
6Institut für Theoretische Astrophysik, Tiergartenstra&ssharp;e 15, D-69121 Heidelberg, Germany (rzylka@ita.uni-heidelberg.de)

The Astrophysical Journal (1998), Vol. 499, (June 1, 1998), in press


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.

Paper: Available in PostScript and (AAS)LaTex.

Other publications can be found here.

Questions: Heino Falcke, hfalcke@mpifr-bonn.mpg.de