The Supergiant Shell LMC 2. II. Physical Properties of the 106K Gas

LMC2 has the highest X-ray surface brightness of all know supergiant shellsin the Large Magellanic Cloud (LMC). The X-ray emission peaks within theionized filaments that define the shell boundary, but also extends beyond thesouthern border of LMC2 as an X-ray bright spur. ROSAT HRI images reveal theX-ray emission from LMC2 and the spur to be truly diffuse, indicating a hotplasma origin. We have obtained ROSAT PSPC and ASCA SIS spectra to study thephysical conditions of the hot gas interior to LMC2 and the spur. Raymond-Smiththermal plasma model fits to the X-ray spectra, constrained by HI 21-cmemission-line measurements of the column density, show the plasma temperatureof the hot gas interior of LMC2 to be kT = 0.1 - 0.7 keV and of the spur to bekT = 0.1 - 0.5 keV. We have compared the physical conditions of the hot gasinterior to LMC2 with those of other supergiant shells, superbubbles, andsupernova remnants (SNRs) in the LMC. We find that our derived electrondensities for the hot gas inside LMC2 is higher than the value determined forthe supergiant shell LMC4, comparable to the value determined for thesuperbubble N11, and lower than the values determined for the superbubble N44and a number of SNRs.Comment: 29 pages, 5 figures, to be published in Ap