P. J. Puxley
S. K. Ramsay Howat
C. M. Mountain
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720
Astronomical Technology Centre, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ, UK
Gemini Observatory Northern Operations Center, 670 N. A'ohoku Place, Hilo HI 96720
We present a sensitive 2µm spectrum of the extragalactic giant HII complex NGC5461. The spectrum contains detections of vibrationally excited molecular hydrogen transitions from energy levels up to 19000K. Comparison of the line emission with models of excitation in photon dominated regions demonstrates unambiguously that the gas is excited by the UV light from the newly formed stars. We derive an abundance ratio of ortho-to-para states in the excited gas of 1.15±0.11 which is amongst the lowest ever recorded.
Appears in the Astrophysical Journal, January 2000.
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