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dc.contributor.advisorHsieh, Ke-Chiangen_US
dc.contributor.authorKwok, Ping Wai.
dc.creatorKwok, Ping Wai.en_US
dc.date.accessioned2011-10-31T17:20:48Z
dc.date.available2011-10-31T17:20:48Z
dc.date.issued1989en_US
dc.identifier.urihttp://hdl.handle.net/10150/184863
dc.description.abstractThis project is to search for Very High Energy (VHE) (10¹¹ eV to 10¹⁴ eV) gamma rays from the Crab nebula and pulsar using the atmospheric Cherenkov imaging technique. The technique uses an array of 37 photomultiplier tubes to record the images of the Cherenkov light pulses generated by energetic particles in the air showers initiated by VHE gamma rays or charged cosmic rays. Gamma-ray-like events are selected from numerous cosmic-ray events based on the predicted properties of the image, such as the size, shape, and orientation with respect to the axis of the detector. A steady weak flux of VHE gamma rays from the Crab is detected at high statistical significance (9 sigma), which is not usually achieved in VHE gamma-ray astronomy. No strong evidence of pulsed emission is found when the same data is folded at the Crab pulsar's radio ephemeris. The angular resolution of the technique cannot separate the emission coming from the nebula from that from the pulsar. Although it is generally believed that the unpulsed emission is coming from the nebula, there may be an unpulsed component coming at only a couple of light cylinder radii away from the pulsar too. Using the outer gap model of pulsar, the spectrum is derived and is found to be compatible with the observations.
dc.language.isoenen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.subjectGamma ray sources.en_US
dc.subjectCrab Nebula.en_US
dc.subjectGamma ray astronomy.en_US
dc.titleVery high-energy gamma rays from the Crab nebula and pulsar.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc703430151en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.contributor.committeememberParmenter, Roberten_US
dc.contributor.committeememberHill, Henryen_US
dc.contributor.committeememberBowen, Theodoreen_US
dc.contributor.committeememberMcIntyre, Laurenceen_US
dc.identifier.proquest9010482en_US
thesis.degree.disciplinePhysicsen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-14T02:07:03Z
html.description.abstractThis project is to search for Very High Energy (VHE) (10¹¹ eV to 10¹⁴ eV) gamma rays from the Crab nebula and pulsar using the atmospheric Cherenkov imaging technique. The technique uses an array of 37 photomultiplier tubes to record the images of the Cherenkov light pulses generated by energetic particles in the air showers initiated by VHE gamma rays or charged cosmic rays. Gamma-ray-like events are selected from numerous cosmic-ray events based on the predicted properties of the image, such as the size, shape, and orientation with respect to the axis of the detector. A steady weak flux of VHE gamma rays from the Crab is detected at high statistical significance (9 sigma), which is not usually achieved in VHE gamma-ray astronomy. No strong evidence of pulsed emission is found when the same data is folded at the Crab pulsar's radio ephemeris. The angular resolution of the technique cannot separate the emission coming from the nebula from that from the pulsar. Although it is generally believed that the unpulsed emission is coming from the nebula, there may be an unpulsed component coming at only a couple of light cylinder radii away from the pulsar too. Using the outer gap model of pulsar, the spectrum is derived and is found to be compatible with the observations.


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