The Nature and Origin of Large Scale Diffuse X -Ray Emission in the Large Magellanic Cloud

X-ray mosaics of the Large Magellanic Cloud (LMC) taken with the ROSAT Position Sensitive Proportional Counter (PSPC) have revealed extensive diffuse X-ray emission, indicative of hot ≳ 106 K gas associated with this irregular galaxy on scales from ∼10 pc to ≥1000 pc. Here we examine the nature and origin of the large scale diffuse X-ray emission from the LMC. We first examine the large scale spatial distribution and physical conditions of hot gas in the LMC. We find that although the large scale diffuse X-ray emission with the highest X-ray surface brightness is usually associated with supergiant shells in the LMC, the bulk of the large scale diffuse X-ray emission is associated with field gas. To better understand the production of ≳ 106 K gas in the LMC, we examine the physical structure of the multi-phase interstellar medium (ISM) of supergiant shells in the LMC using LMC2 as a detailed case study because it has the highest X-ray surface brightness of all supergiant shells in the LMC. Neither Halpha nor H I 21-cm line observations of LMC2 show an unambiguous signature of a coherent expanding shell. These data allow us to better interpret observations of supergiant shells in more distant (≥4 Mpc) galaxies. X-ray spectra show the plasma temperature of the hot gas interior to LMC2 to be kT ∼ 0.1--0.7 keV. The derived electron densities for the hot gas inside LMC2 is higher than the electron densities for other supergiant shells in the LMC, but are comparable to or lower than those of superbubbles and supernova remnants in the LMC. Finally, we have investigated the production of the ≳ 106 K gas by the underlying stellar population of LMC2. We find tentative evidence that the hot ≳ 106 K gas content of LMC2 can be produced by its underlying massive stellar population. This is the first time detailed observations of the multiphase ISM of a supergiant shell has been examined in conjuction with the resolved massive stellar population.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Astronomy

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Points, Sean Daniel

Contributors dc:contributor

• Chu, You-Hua

• Physics, Astronomy and Astrophysics

Language dc:language

eng

Identifier

(MiAaPQ)AAI3023173

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/85169