The 1720 MHz OH Emission from G359.1-0.5 and the CND

F. Yusef-Zadeh(1), B.T. Robinson(1), D.A. Roberts(2), W.M. Goss(3), D.A. Frail(3), and A. Green (4)

(1) Northwestern University, Dept Physics and Astronomy, Evanston, IL 60208, US
(2) NCSA, 405 N. Mathews Ave, Urbana, IL 61801
(3) NRAO, P.O. Box 0, Socorro, NM 87801
(4) University of Sydney, School of Physics, Sydney, NSW 2006

Paper: to appear in the Proc. of the 4th ESO/CTIO Workshop "The Galactic Center", Ed. R. Gredel


VLA observations of the CND, which surrounds Sgr A West, and G359.1-0.5 have been carried out at the 1720 MHz transition of the OH molecule. 1720 MHz OH maser emission has been detected from the CND and G359.1-0.5 at velocities near V_LSR = +132 and -5 km/s, respectively. The OH maser features toward G359.1-0.5 have been detected along the interface between a large-scale non-thermal continuum shell G359.1-0.5 and its surrounding ring of high velocity molecular CO gas. The V spectra of a number of bright maser sources associated with the CND and G359.1-0.5 suggest strong magnetic fields between 0.4 and 4 mG. We argue that these masers are produced at the boundaries of G359.1-0.5 and the CND and that the maser features signify regions of shocked gas resulting from the supernova expansion and from cloud-cloud collisions at the Galactic center.

Preprints available from the authors at ZADEH@OSSENU.ASTRO.NWU.EDU , or the raw TeX (no figures) if you click here.

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