Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-10-27
Astronomy and Astrophysics
Astrophysics
26 pages, 16 figures, accepted for publication in the Astrophysical Journal Supplement
Scientific paper
10.1086/523897
Nine supergiant shells (SGSs) have been identified in the Large Magellanic Cloud (LMC) based on H-alpha images, and twenty-three SGSs have been reported based on HI 21-cm line observations, but these sets do not always identify the same structures. We have examined the physical structure of the optically identified SGSs using HI channel maps and P-V diagrams to analyze the gas kinematics. There is good evidence for seven of the nine optically identified SGSs to be true shells. Of these seven H-alpha SGSs, four are the ionized inner walls of HI SGSs, while three are an ionized portion of a larger and more complex HI structure. All of the H-alpha SGSs are identified as such because they have OB associations along the periphery or in the center, with younger OB associations more often found along the periphery. After roughly 12 Myrs, if no new OB associations have been formed a SGS will cease to be identifiable at visible wavelengths. Thus, the presence and location of ionizing sources is the main distinction between shells seen only in HI and those also seen in H-alpha. Based on our analysis, H-alpha observations alone cannot unambiguously identify SGSs, especially in distant galaxies.
Book Laura G.
Chu Y.-H. Y.-H.
Gruendl Robert A.
No associations
LandOfFree
Structure of Supergiant Shells in the Large Magellanic Cloud 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 Structure of Supergiant Shells in the Large Magellanic Cloud, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Structure of Supergiant Shells in the Large Magellanic Cloud will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-236744