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Title: On the origins of cosmic dust and the evolution of nearby galaxies with the Herschel Space Observatory
Author: Clark, Christopher
ISNI:       0000 0004 5352 4035
Awarding Body: Cardiff University
Current Institution: Cardiff University
Date of Award: 2014
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USING multiwavelength observations, centred around the unique far-infrared and submillimetre window provided by the Herschel Space Observatory, this thesis investigates the origins and evolution of cosmic dust in the local Universe – by examining individual sources of dust in our own galaxy, and by studying dust in nearby galaxies. Herschel observations of the remnants of Kepler’s (SN1604) and Tycho’s (SN1572) supernovae, both Type-Ia explosions, are searched for evidence of dust creation by these events. Being the only Type-Ia supernovae known to have occurred in our Galaxy within the past 1,000 years, these remnants are the only ones both close enough to resolve, and young enough that they are dominated by their ejecta dynamics. There is no indication of any recently manufactured dust associated with either supernova remnant. It therefore appears that Type-Ia supernovae do not contribute significantly to the dust budgets of galaxies. The Crab Nebula, the result of a Type-II supernova (SN1054), is also investigated using Herschel and multiwavelength data. After accounting for other sources of emission, a temperature of Td = 63.1K and mass of Md = 0.21M⊙ is derived for the Crab Nebula’s dust component. A map of the distribution of dust in the Crab Nebula, the first of its kind, is created by means of a resolved component separation, revealing that the dust is located in the dense filamentary ejecta. We can be confident that this dust will survive in the long term, and be injected into the galactic dust budget. This is the first detection of manufactured supernova dust for which this can be said. I next use the Herschel-ATLAS to assemble HAPLESS: the Herschel-ATLAS Phase-1 Limited Extent Spatial Sample – a blind, volume-limited, dust-selected sample of nearby galaxies. The majority of this sample is made up of curious very blue UV-NIR colours, these galaxies appear to be prominent in the local dusty universe. In the absence of reliable photometry for the HAPLESS galaxies, I describe the function and testing of a purpose-built photometric pipeline – CAAPR: Chris’ Adequate Aperture Photometry Routine. The photometry conducted with CAAPR exhibits flux greater by factors of, on average, 1.6 in the FUV and 1.4 in r-band, relative to the previously-available photometry.
Supervisor: Not available Sponsor: Science and Technology Facilities Council
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QB Astronomy