Fluorescence of [Fe II] in H II regions *
Received 14 April 1999 / Accepted 21 May 1999
A study of [FeII] lines at various positions within the HII regions M42 and M43 is presented. The relative intensities of selected optical [FeII] lines are shown to be correlated with the intensity of the apparent nebular continuous spectrum. Since the continuum of HII regions is known to be mostly stellar radiation scattered by dust intermixed with the emitting gas, these correlations provide direct evidence for the existence of fluorescent excitation in the formation process of the [FeII] lines, irrespective of the prevailing physical state.
Key words: ISM: H ii regions line: formation ISM: individual objects: M42 ISM: individual objects: M43
* Based on observations made with the Isaac Newton Telescope, operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.
© European Southern Observatory (ESO) 1999
Online publication: July 16, 1999