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                              G C N E W S
                             * Newsflash *

            - The Newsletter for Galactic Center Research -

gcnews@mpifr-bonn.mpg.de             http://www.mpifr-bonn.mpg.de/gcnews
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Vol. 9, No. 9                                              Nov 20, 1998


Recently submitted papers:
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Email    : lazio@rsd.nrl.navy.mil
Title    : G359.87+0.18: An FR II Radio Galaxy 15 Arcminutes from Sgr 
           A*. Implications for the Scattering Region in the 
           Galactic Center
Author(s): T. Joseph W. Lazio(1,2), K. R. Anantharamaiah(3,4). W. M. 
           Goss(3), Namir E. Kassim(5), James M. Cordes(6)
Institute: (1) NRL, Code 7210, Washington, DC, 20375-5351;    
           lazio@rsd.nrl.navy.mil   (2) NRC-NRL Research Associate   
           (3) NRAO, P. O. Box 0, Socorro, NM 87801; 
           anantha@aoc.nrao.edu;    mgoss@nrao.edu   (4) On leave from 
           Raman Research Institute, Bangalore    560 080, India   (5) 
           NRL, Code 7213, Washington, DC, 20375-5351;    
           nkassim@rsd.nrl.navy.mil   (6) Department of Astronomy, 
           Cornell University and NAIC, 520 Space    Sciences Bldg., 
           Ithaca, NY, 14853-6801;    cordes@spacenet.tn.cornell.edu
Paper    : to appear in ApJ, vol. 515, 1998 April 1
EPrint   : astro-ph/9811317

Abstract:
G359.87+0.18 is an enigmatic object located 15' from Sgr A*.  It has
been variously classified as an extragalactic source, Galactic jet
source, and young supernova remnant.  We present new observations of
G359.87+0.18 between 0.33 and 15 GHz and an HI absorption spectrum and
use these to argue that this source is an Faranoff-Riley II radio
galaxy.  We are able to place a crude limit on its redshift of z >~
0.1.  The source has a spectral index alpha < -1 (S \propto nu^alpha),
suggestive of a radio galaxy with a redshift z >~ 2.  The scattering
diameters of Sgr A* and several nearby OH masers (~ 1'' at 1 GHz)
indicate that a region of enhanced scattering is along the line of
sight to the Galactic center.  If the region covers the Galactic
center uniformly, the implied diameter for a background source is at
least 600'' at 0.33 GHz, in contrast with the observed 20'' diameter
of G359.87+0.18.  Using the scattering diameter of a nearby OH maser
OH 359.762+0.120 and the widths of two, nearby, non-thermal threads,
G0.08+0.15 and G359.79+0.17, we show that a uniform scattering region
should cover G359.87+0.18.  We therefore conclude that the Galactic
center scattering region is inhomogeneous on a scale of 5' (~ 10 pc at
a distance of 8.5 kpc).  This scale is comparable to the size scale of
molecular clouds in the Galactic center.  The close agreement between
these two lengths scales is an indication that the scattering region
is linked intimately to the Galactic center molecular clouds.

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			       Edited by
Angela Cotera                                Heino Falcke
(cotera@ipac.caltech.edu)                    (hfalcke@mpifr-bonn.mpg.de)
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