A search for forbidden O III lambda 5007 lines in the Galactic background was carried out in three directions with the Wisconsin 15 cm Fabry-Perot spectrometer. The forbidden O III line was detected in two directions in the Galactic plane with an intensity of 2 x 10 to the -7th ergs/sq cm s sr, which is approximately 0.06 the background H-alpha intensity. An upper limit of 5 x 10 to the -8th ergs/sq cm s sr has been placed on the forbidden O III lambda 5007 line intensity in a high-latitude (b = -30 deg) direction. Although the source of this very faint forbidden O III line emission is not yet known, these observations place important constraints on the origin of the warm (about 10,000 K), ionized component of the diffuse interstellar medium and on the amount of higher temperature (about 10 to the 5th K) gas that may be present.
No takes yet. Share an insight, caveat, or question.
R. J. Reynolds (1985) studied this question.