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L.M. Haffner, R.J. Reynolds, G.J. Madsen (UW--Madison), S.L. Tufte (Lewis & Clark), K.P. Jaehnig, J.P. Percival (UW--Madison (SAL)), N.R. Hausen (UW--Madison)
The ionized gas in the Milky Way has been fully surveyed from the Northern Hemisphere by the Wisconsin H-Alpha Mapper (WHAM). The WHAM Northern Sky Survey (WHAM-NSS) has an angular resolution of one-degree and provides the first kinematically resolved map of the Warm Ionized Medium (WIM). With 12 km s-1 spectral resolution, we have removed atmospheric emission and zodiacal absorption features from each of the 37,565 spectra, leaving behind a fully resolved Galactic H\alpha profile. Galactic emission is detected in nearly every spectrum.
Velocity channel maps from the survey show complex filamentary structure in the local WIM and in the nearest spiral arms. Some of these halo features are clearly associated with active star formation in the Galactic plane. High-latitude H\alpha emission at intermediate velocities traces out IVC complexes previously discovered through 21 cm observations. An initial analysis of the relationship between the high latitude H\alpha and 21 cm emission suggests that although the spatial extent and velocity profiles are quite similar, the intensities are completely uncorrelated. Our deep emission sensitivity also reveals several \ion{H}{2} regions around early B stars and sdO stars, providing an indirect probe of their Lyman continuum and adding another ionizing source for the WIM.
Total intensity maps, velocity channel maps, and full spectral profiles from the WHAM-NSS are available for download at {\tt http://www.astro.wisc.edu/wham/}.
WHAM was built and continues to explore the rich science of ionized gas through generous support of the National Science Foundation. This work is funded by grant AST96-19424.
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The author(s) of this abstract have provided an email address for comments about the abstract: haffner@astro.wisc.edu