AAS 199th meeting, Washington, DC, January 2002
Session 85. The Galactic Center
Display, Wednesday, January 9, 2002, 9:20am-6:30pm, Monroe/Lincoln

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[85.06] Temperature, Opacity, and Kinematics of NH3 at the Galactic Center

R.S. McGary, P.T.P. Ho (CfA), A.L. Coil (UC-Berkeley)

Mosaics of the central 10 pc made with the VLA show that NH3 (1,1), (2,2) and (3,3) trace many filamentary streams of gas and giant molecular clouds (GMCs) near the Galactic Center (McGary et al. 2001). The images show the well-known ``southern streamer,'' ``50 km/s cloud,'' and new features including a ``western streamer'', 6 parsecs in length, and a ``northern ridge'' which connects to the Circumnuclear Disk (CND). These NH3 images have a spatial resolution of 16.5''x14.5'' and fully sample the inner 10 pc of the Galaxy. In addition, the new data cover a velocity range of 270 km/s , including all velocities observed in the CND, with a resolution of 9.8 km/s.

In this poster, we present the kinematics and physical properties of the features that we observed in our integrated velocity maps in McGary et al. (2001). Kinematic evidence for at least two connections between the GMCs and clouds close to the nucleus are presented. Additional features with high velocity gradients (up to 25 km/s/pc) are also shown. The data from these three NH3 transitions allow us to estimate additional physical parameters. The hyper-fine lines bracketing each main NH3 line enable a determination of the opacity of the gas. In addition, line ratios can be used to directly calculate the rotational temperature of the clouds that we observe. Temperature information is especially important for determining which features are undergoing shocks or are being heated by the nucleus. We observe a general trend towards warmer gas near the nucleus. The ''western streamer'' which appears to have been swept up by the expansion of Sgr A East also appears to have high temperatures. Both opacity and temperature maps for the central 10 pc will be presented.

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