The simultaneous spectrum of Sgr A* from lambda 20cm to lambda 1mm and the nature of the mm-excess
Heino Falcke(1,2), W.M. Goss(3), Hiroshi Matsuo(4), Peter Teuben(1), Jun-Hui Zhao(5), Robert Zylka(6)
(1) Astronomy Department, University of Maryland, College Park, MD 20742-2421 (hfalcke,teuben@astro.umd.edu)
(2) Current Address: Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn, Germany (hfalcke@mpifr-bonn.mpg.de)
(3) NRAO, P.O. Box O, Socorro, NM 87801-0387 (mgoss@nrao.edu)
(4) Nobeyama Radio Observatory, Minamimaki, Minamisaku, Nagano 384-13, Japan (matsuo@nro.nao.ac.jp)
(5) Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (jzhao@cfa.harvard.edu)
(6) Institut für Theoretische Astrophysik, Tiergartenstraße 15, D-69121 Heidelberg, Germany (rzylka@ita.uni-heidelberg.de)
Paper: ApJ, in press
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.
Preprints available from the authors at hfalcke@mpifr-bonn.mpg.de
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or the raw TeX (no figures) if you click here.
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