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Title: XMM-Newton observations of the Galactic Centre region
Author: Heard, Victoria
ISNI:       0000 0004 2744 3389
Awarding Body: University of Leicester
Current Institution: University of Leicester
Date of Award: 2013
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X-ray observations of the Galactic Centre (GC) can provide invaluable insight into the physical processes within this unique region. In this thesis we investigate the nature of the GC diffuse X-ray emission. We have utilised archival XMM-Newton data to create image mosaics of the central 100 pc region in both continuum bands spanning the 2–10 keV energy range and in a set of narrow bands encompassing various emission lines. We use these mosaics, along with complementary X-ray spectral information, to show that the bulk of the very-hot thermal emission (kT ~ 7:5 keV) can be explained in terms of a population of unresolved point sources, most likely magnetic CVs. Our analysis argues against the requirement for significant amounts of very-hot diffuse plasma. We also investigate a number of soft thermal features. We propose that the putative outflow from Sgr A* may result from the collimated winds of massive stars in the Central Cluster, or alternatively from outbursts on the central supermassive black hole. We show that the characteristics of the soft thermal emission to the north-east of Sgr A* are consistent with those of a mixed- morphology supernova remnant. The final feature considered is a looped structure to the south of the Galactic Plane. Our analysis supports the hypothesis that this is a superbubble deriving from the interaction of supernova shocks with the surrounding ISM. We also investigate the nature and properties of the intermediate-to-faint Galactic Bulge point source population based on a sample of 3610 X-ray source detections from the 2XMMi-DR3 catalogue. We conclude that the spectrally-soft sources are largely coronally-active systems, whereas the spectrally-hard sources are a more heterogeneous set, albeit the majority of which are accreting binaries.
Supervisor: Warwick, Robert Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available