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Molecular Hydrogen Emission from the Inner 400 Parsecs of the Galaxy

Soojong Pak·D. T. Jaffe·L. D. Keller
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Abstract

We have mapped the H_2 v=1-0 S(1) (λ=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.

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Soojong Pak, D. T. Jaffe, L. D. Keller. 1996-04-29. Molecular Hydrogen Emission from the Inner 400 Parsecs of the Galaxy. https://doi.org/10.1086/309881

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