We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.

Durham e-Theses
You are in:

Ultra high energy gamma ray point sources and cosmic ray anisotropy

Graham, Lilian Joan (1994) Ultra high energy gamma ray point sources and cosmic ray anisotropy. Doctoral thesis, Durham University.



The experimental set-up at the Baksan Air Shower Array, used to detect air showers above ~0.2xl0(^14)eV, is described. An estimation of the angular resolution using the cosmic ray shadow of the Sun and the Moon gives a value of ~2.5˚ which is consistent with previous estimates from Monte-Carlo simulations. Using data from this array covering 1985-1992, a search is made for 7-ray emission from 18 candidate sources. Upper limits to the flux from these sources are stated in all cases. A periodicity search is made on data for which the excess for a single transit of a particular source is above 3(7. The results of this periodicity analysis on such days points to 4 possible observations of pulsed emission at the 95% confidence level. These are 4U0115+63 on 19.03.89, PSR19534-29 on 12.02.85, 1E2259+586 on 01.08.91 and PSR0655+64 on 12.08.89. Without confirmation from other groups however the findings are not significant enough to stand alone. A harmonic analysis has been performed on the 8 years of data and after pressure corrections and a Farley & Storey analysis to eradicate any spurious sidereal variations we find negligible evidence of 2nd or 3rd harmonic but a 1st harmonic amplitude and phase of (12.7 ±1.2) x 10(^-4) at 23.1 ± 0.3hr right ascension. When one takes into account the cosϐ effect on the sidereal anisotropy this value becomes 17.4±1.6xl0(^-4).Future developments and improvements to be undertaken at BASA, including the building of a muon detector, are outlined.

Item Type:Thesis (Doctoral)
Award:Doctor of Philosophy
Thesis Date:1994
Copyright:Copyright of this thesis is held by the author
Deposited On:16 Nov 2012 10:50

Social bookmarking: del.icio.usConnoteaBibSonomyCiteULikeFacebookTwitter