Molecular Hydrogen Emission from the Inner 400 Parsecs of the Galaxy
  We have mapped the H_2 v=1-0 S(1) (\lambda=2.1215 \micron) emission line along a 400 pc long strip and in a 50 pc region in the Galactic center. There is H_2 emission throughout the surveyed region. The typical de-reddened (A_K = 2.5 mag) surface brightness, about 3 X 10^{-5} ergs/s/cm^2/sr, is similar to the surface brightness in large-scale photon-dominated regions in the galactic disk. We investigate two possible excitation mechanisms for the H_2 emission: UV-excitation by photons from OB stars, and shock waves, and conclude that UV-excitation is more likely. The total H_2 v=1-0 S(1) luminosity in the inner 400 pc region of the Galaxy is 8000 L_sun. The ratio of the H_2 to far-IR luminosity in the inner 400 pc of the Galaxy agrees with that in starburst galaxies and ultraluminous infrared bright galaxies. 
Soojong Pak, D. T. Jaffe, and L. D. Keller (Astronomy Department,   University of Texas at Austin)