| Type |
Conference Paper |
| Names |
Martin Gostisha, R. A. Benjamin, L. M. Haffner |
| Proceedings Title |
Bulletin of the American Astronomical Society |
| Conference Name |
American Astronomical Society, AAS Meeting #217, #251.08 |
| Volume |
43 |
| Date |
January 1, 2011 |
| URL |
http://adsabs.harvard.edu/abs/2011AAS...21725108G |
| Library Catalog |
NASA ADS |
| Abstract |
We present a Wisconsin H-alpha Mapper (WHAM) survey of the fourth
quadrant of the Galactic plane in diffuse emission from [S II] 6716 A,
covering Galactic longitude l=270-360 degrees and latitude |b|<12
degrees. One of the more prominent features seen is a large-scale
ionized bubble, centered at l=320.0 deg, b=3.4 deg with a diameter of 7
degrees. Spectra of the center of this region shows line splitting
characteristic of an expanding bubble. A search for high mass star in
the region shows that this bubble subtends over 40 O stars, including
the cluster Pismis 20 which is part of the Circinus OB association.
Assuming that the bubble is at the distance of this cluster, yields a
bubble diameter of 300 parsec. When this is combined with the measured
expansion velocity of 7 km/s, we derive a bubble age of approximately 2
Myrs, consistent with the estimated age of the Circinus OB association.
We discuss the energetics of the bubble as well as the result of
searching for this bubble using tracers at other wavelengths. This
research was supported the NSF REU site grant to the University of
Wisconsin-Madison. |