A Study of the Muon Content of EAS Initiated by UHE Gamma-Ray Emission from Cygnus X-3.
Abstract
Available from UMI in association with The British Library. Requires signed TDF. The main concern of this thesis is the determination of the muon content of extensive air showers (EAS) initiated by ultra high energy (UHE) gamma -ray emission from the Galactic X-ray binary Cygnus X-3. The results of observations of Cygnus X-3 made with the Gamma Ray experiment (GREX) at Haverah Park between 17th April 1986 and 30th September 1988 are presented. GREX is a fast timing scintillator array, sensitive to air showers of primary energy greater than ~2 times 10^{rm 14}eV per particle. It has good angular resolution (better than 1^circ) and was specifically designed for the study of gamma -ray emission from point sources. The GREX array, operated by the University of Leeds Cosmic Ray Group, provides the EAS trigger for the University of Nottingham's 40m ^2 muon detector, which is situated at the centre of the array. Following a brief survey of cosmic ray physics, the emission characteristics of Cygnus X-3 ranging over 22 decades of energy are described in detail. A review of the theoretical predictions and recent experimental measurements of the muon content of EAS induced by UHE gamma-rays is then given. The muon detector is then described in detail and techniques for determining its response to individual showers are outlined. Background data are then used to establish average air shower characteristics, against which to compare the muon content of showers initiated by UHE gamma-rays. After a description of the analysis techniques adopted in this work, the results of the analysis of data recorded during the periods 17th April 1986 to 29th June 1987 and 30th June 1987 to 30th September 1988 are presented. No evidence for significant time-averaged emission from Cygnus X-3 for all, or muon content selected, events was found in either period. Orbital phase analysis of events recorded during the period 17th April 1986 to 29th June 1987 gave some indication that muon-poor selection does not help to enhance a signal; indeed only a muon-rich cut applied to this data provided some evidence for a phase modulated signal from Cygnus X-3. This effect was not confirmed in the phase analysis of data recorded during the period 30th June 1987 to 30th September 1988. Such an observation is shown to be compatible with contemporaneous measurements indicating weak emission during this time.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1990
- Bibcode:
- 1990PhDT.........3E
- Keywords:
-
- Physics: Astronomy and Astrophysics, Physics: Elementary Particles and High Energy;
- Cosmic Ray Showers;
- Cygnus Constellation;
- Emission Spectra;
- Gamma Ray Astronomy;
- Muons;
- Stellar Spectra;
- X Ray Binaries;
- Cosmic Rays;
- Gamma Rays;
- Scintillation Counters;
- X Rays;
- Space Radiation