OH(1720 MHz) Masers at the Galactic Center
OH(1720 MHz) masers permit direct measurements of the magnetic field strength at the Galactic Center, and their angular broadening constrains models for the medium that scatters radio waves in the central 100 pc of the Galaxy. As the 1720 MHz masers are unaccompanied by the main-line masers at 1665 and 1667 MHz, they must be pumped by collisions in molecular gas that is cooling after being overrun by a non-dissociative (i.e. C-type) shock wave. In particular, this confirms that the ``SNR'' Sgr A East is driving a shock into the M-0.02-0.07 molecular cloud. The intensity of the v = 1--0 S(1) line of H2 is consistent with the shock strength expected to be driven into the molecular gas by the pressure within Sgr A East.
The Central Parsecs of the Galaxy
- Pub Date:
- June 1999
- To appear in proceedings of "The Central Parsecs", Tucson Sept 7-11 1998. 9 pp incl 4 figs, LaTeX, uses epsf.sty paspconf.sty