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Fermi satellite observations of gamma-ray counterparts to radio and x-ray binaries

Ali, Mohamed Omar (2014) Fermi satellite observations of gamma-ray counterparts to radio and x-ray binaries. PhD thesis, University of Leeds.

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With the advent of the Fermi Large Area Telescope (Fermi hereafter), the total number of gamma-ray sources has almost reached 2000 and continues at a rapid pace. The second catalog was released in 2012 and contained 1873 sources, with only 127 of those sources firmly identified. The large number of unidentified sources means that interesting physics could be discovered. This thesis will present a study of the gamma-ray emission from X-ray and radio binary systems using the Fermi satellite. A review of gamma-ray binaries is presented with examples of sources detected by Fermi. Gamma-ray emission mechanisms are discussed with particular focus on those likely to be detected from binary systems. The connection between X-ray, radio and gamma-ray emission is discussed with emphasis on the features that can be searched in the Fermi observations. A review of gamma-ray telescopes leading up to the Fermi satellite is presented followed by detailed discussion of the Fermi event reconstruction, classification and background rejection. The Fermi detecter point spread function, energy dispersion and effective area are shown followed by an overview of the recommended Fermi data analysis threads used throughout the thesis. The current status of gamma-ray binaries that have already been observed with Fermi and the features that could potentially be observed on other binaries is discussed. The techniques used in this thesis including temporal, statistical, cross correlation and pulsar gating are presented. The analysis and results from known Fermi gamma-ray sources Cygnus X-3 and PSR B1259-63 are presented along side a possible detection of Circinus X-1. The 4.8 hour orbital period of Cygnus X-3 is clearly observed after the application of the pulsar gating technique. PSR B1259-63 is simultaneously observed for the first time in GeV during its periastron passage. A flare is also observed 15 days after periastron which is not detected in radio, X-ray and TeV. Two catalogues containing radio and X-ray binary systems are analysed using Fermi data and the results presented. Three sources are found to be of interest and further analysed as potential gamma-ray candidates. Although no definitive detections were obtained, the upper limits in gamma-ray flux provide a good starting point for future observations with Fermi and other gamma-ray detectors.

Item Type: Thesis (PhD)
ISBN: 978-0-85731-822-0
Academic Units: The University of Leeds > Faculty of Maths and Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds)
Identification Number/EthosID: uk.bl.ethos.617308
Depositing User: Repository Administrator
Date Deposited: 11 Sep 2014 14:09
Last Modified: 25 Nov 2015 13:45
URI: http://etheses.whiterose.ac.uk/id/eprint/6869

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