Stellar Energy Feedback in Superbubbles

155 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2007.In the first study of this thesis, optical and X-ray observations have been used to probe the nature of the ultraluminous supernova remnant (SNR) MF16 in NGC6946 and explore a single star's interaction with the ISM. The second study presents observations of diffuse X-ray emission from the superbubble in M17. The stellar population in M17 is young, only 1 million years old, suggesting no supernovae have occurred and providing a rare opportunity to test the predictions of wind-blown bubble models on superbubble scales without confusion from supernovae. The third study presents X-ray observations of thirteen superbubbles in the Large Magellanic Cloud (LMC). The diffuse X-ray emissions from these superbubbles are brighter than expected for wind-blown bubbles, suggesting that the emissions have been enhanced by interactions between the shells and interior SNRs. In the fourth study, 21-cm radio observations are used to examine the kinematics of the neutral gas components of sixteen LMC superbubbles. For comparison, we have used previous observations in hydrogen alpha-line emission to determine the kinematics of their ionized gas components. In the final study, the energy feedback efficiencies of the superbubbles N11 and N44 in the LMC are examined. The injected energies absorbed by the shells have been determined, and the stellar input energies have been estimated from the populations of the OB associations. N11 is found to have an energy conversion efficiency of one-third, while the conversion efficiency of N44 is lower, one-fifth. These results demonstrate the "energy crisis" in understanding the physics of stellar energy feedback.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD