| Type |
Journal Article |
| Names |
L. M. Haffner, R. J. Reynolds, S. L. Tufte, G. J. Madsen, K. P. Jaehnig, J. W. Percival |
| Publication |
The Astrophysical Journal Supplement Series |
| Volume |
149 |
| Issue |
2 |
| Pages |
405-422 |
| Date |
December 1, 2003 |
| URL |
http://adsabs.harvard.edu/abs/2003ApJS..149..405H |
| Library Catalog |
NASA ADS |
| Abstract |
The Wisconsin Hα Mapper (WHAM) has surveyed the distribution and
kinematics of ionized gas in the Galaxy above declination -30°. The
WHAM Northern Sky Survey (WHAM-NSS) has an angular resolution of 1°
and provides the first absolutely calibrated, kinematically resolved map
of the Hα emission from the warm ionized medium (WIM) within
~+/-100 km s-1 of the local standard of rest. Leveraging
WHAM's 12 km s-1 spectral resolution, we have modeled and
removed atmospheric emission and zodiacal absorption features from each
of the 37,565 spectra. The resulting Hα profiles reveal ionized
gas detected in nearly every direction on the sky with a sensitivity of
0.15 R (3 σ). Complex distributions of ionized gas are revealed in
the nearby spiral arms up to 1-2 kpc away from the Galactic plane.
Toward the inner Galaxy, the WHAM-NSS provides information about the WIM
out to the tangent point down to a few degrees from the plane. Ionized
gas is also detected toward many intermediate velocity clouds at high
latitudes. Several new H II regions are revealed around early B stars
and evolved stellar cores (sdB/O). This work presents the details of the
instrument, the survey, and the data reduction techniques. The WHAM-NSS
is also presented and analyzed for its gross properties. Finally, some
general conclusions are presented about the nature of the WIM as
revealed by the WHAM-NSS. |
| Tags |
Galaxy: halo, ISM: Atoms, ISM: H II Regions, ISM: structure |