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The Nature, Location and Environment of Sgr A East

Published online by Cambridge University Press:  23 September 2016

W. M. Goss ,
K. R. Anantharamaiah ,
J. H. van Gorkom ,
R. D. Ekers ,
A. Pedlar ,
U. J. Schwarz  and
Jun-Hui Zhao
W. M. Goss
Affiliation:
NRAO/VLA, Socorro, New Mexico, USA
K. R. Anantharamaiah
Affiliation:
NRAO/VLA, Socorro, New Mexico, USA
J. H. van Gorkom
Affiliation:
NRAO/VLA, Socorro, New Mexico, USA
R. D. Ekers
Affiliation:
Australia Telescope, Epping, NSW, Australia
A. Pedlar
Affiliation:
NRAL, Jodrell Bank, Cheshire, U.K.
U. J. Schwarz
Affiliation:
Kapteyn Astronomical Institute, The Netherlands
Jun-Hui Zhao
Affiliation:
Institute for Astrophysics, UNM, Albuquerque, New Mexico, USA

Abstract

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We have observed SgrA at 332 MHz (92 cm) with a resolution of 12 arcsec (0.6 pc) using the four configurations of the VIA. These results illustrate the dramatic and almost unique variation of radio spectral index within the central 3–4 arcmin of the galactic center. SgrA East is a non-thermal shell source that could be a supernova remnant or a very low-luminosity example of a radio component associated with the active nucleus of a spiral galaxy. The most dramatic aspect of the new 332 MHz observations is the appearance of the the SgrA West spiral features in absorption against SgrA East. Based on these results, SgrA East is situated behind SgrA West, the center of the galaxy. The halo is in front of or surrounds the former sources. The HII regions to the east of SgrA East (1 = −0°.02, b = −0°.07) are probably associated with the 50 km/s molecular cloud. The 7 arcmin halo (20 pc) has a non-thermal spectrum with turn-over below 1 GHz.

Type
The Environment of the SGR A Complex
Information
Symposium - International Astronomical Union , Volume 136: The Galactic Center , 1989 , pp. 345 - 356
Copyright
Copyright © Kluwer 1989 

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