This dissertation describes the search for ultrahigh energy gamma rays from discrete sources with the South Pole Air Shower Experiment (SPASE). The design, configuration, and performance of the telescope are discussed, followed by a description of the techniques used for data analysis. Two novel analysis methods were developed and subsequently applied to the SPASE data base: a neural network was applied to the problem of air shower core location, and a CUSUM method was used to identify gamma-ray bursts. Three years worth of data (1988, 1989, and 1991) were searched for emission of ultrahigh energy gamma radiation from nine pre-defined point sources: the X-ray binaries SMC X-1, LMC X-4, Cen X-3, Vela X-1, 4U1626-67, 4U1145 -61, the super-nova SN1987A, the globular cluster 47 Tucanae, and BL-1, an unconfirmed source that was found by the SPASE group in an earlier all sky survey. No conclusive evidence was found for DC emission from any of the nine candidates. In light of this, upper limits have been set on the time averaged flux detectable by the SPASE array. The four X-ray binaries SMC X-1, LMC X-4, Cen X-3, and Vela X-1, which have well-established orbital periods, were investigated for gamma ray emission modulated with the orbital period. No evidence for a modulated gamma-ray signal was found. A search for sporadic emission from the nine sources was conducted at time scales of one hour, one day, and one week. A statistically significant excess from SMC X-1 (99.6% c.l.) was detected during one day in 1991: 178 events on-source versus 120 background events.
- Pub Date:
- January 1993
- Physics: Astronomy and Astrophysics, Physics: Elementary Particles and High Energy