Detection of [N II] λ5755 Emission from Low-Density Ionized Interstellar Gas

Type Journal Article
Names R. J. Reynolds, N. C. Sterling, L. M. Haffner, S. L. Tufte
Publication The Astrophysical Journal
Volume 548
Issue 2
Pages L221-L224
Date February 1, 2001
URL http://adsabs.harvard.edu/abs/2001ApJ...548L.221R
Library Catalog NASA ADS
Abstract The extremely faint, temperature-sensitive ``auroral'' emission line [N II] λ5755 has been detected from the low-density ionized gas along the sight line toward l=130.0d, b=-7.5d using the Wisconsin Hα Mapper. The intensity of this emission line, relative to the red nebular line [N II] λ6584, is found to be twice that observed in bright, classical H II regions surrounding O stars. This implies that the electron temperature of the ionized gas along this sight line is about 2000 K higher than the H II regions and that the enhanced [N II] λ6584/Hα and [S II] λ6716/Hα intensity ratios in this low-density gas are due at least in part to an elevated temperature.
Tags ISM: General, ISM: H II Regions
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