Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-06-20
Astronomy and Astrophysics
Astrophysics
25 pages, 20 embedded EPS figures, uses emulateapj.sty, to appear in the Astrophysical Journal
Scientific paper
10.1086/342470
We report the discovery of nineteen new HI shells in the Southern Galactic Plane Survey (SGPS). These shells, which range in radius from 40 pc to 1 kpc, were found in the low resolution Parkes portion of the SGPS dataset, covering Galactic longitudes l=253 deg to l=358 deg. Here we give the properties of individual shells, including positions, physical dimensions, energetics, masses, and possible associations. We also examine the distribution of these shells in the Milky Way and find that several of the shells are located between the spiral arms of the Galaxy. We offer possible explanations for this effect, in particular that the density gradient away from spiral arms, combined with the many generations of sequential star formation required to create large shells, could lead to a preferential placement of shells on the trailing edges of spiral arms. Spiral density wave theory is used in order to derive the magnitude of the density gradient behind spiral arms. We find that the density gradient away from spiral arms is comparable to that out of the Galactic plane and therefore suggest that this may lead to exaggerated shell expansion away from spiral arms and into interarm regions.
Dickey John M.
Gaensler Bryan M.
Green Andrew J.
McClure-Griffiths Naomi M.
No associations
LandOfFree
The Galactic Distribution of Large HI Shells does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Galactic Distribution of Large HI Shells, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Galactic Distribution of Large HI Shells will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-330435