Semester

Fall

Date of Graduation

2010

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Physics and Astronomy

Committee Chair

Duncan Lorimer.

Abstract

Pulsars are great tools for studying the Universe. From energetics to radio emission, many of the properties of pulsars can be used to understand other physical phenomena occurring throughout the Universe today. This dissertation examines pulsars and their properties through the use of computer simulations, describes the basic pulsar search procedure, and presents the results of a search for millisecond pulsars (MSPs) and fast radio transients in the Small Magellanic Cloud (SMC).;Using Monte Carlo simulations, a working model of normal pulsars that accurately represents the observed population was created. These simulations allow for changes to be made to the initial spin period, luminosity, braking index, and magnetic field distributions (among others), and the resulting model can be compared to the observed sample of pulsars. These simulations have shown that the luminosity must have some dependence on the spin period and that the braking index has very little effect on the overall pulsar population. Also, it was found to be not possible to produce a self-consistent model of the pulsar population that includes magnetic axis alignment in any of the currently known spin-down laws.;A practical use of these models is the prediction of the results of future pulsar surveys. The model populations can be used to determine the number of pulsars that could be found in a similar survey done with a real telescope. For the purposes of this dissertation, the pulsar population of both the Large and Small Magellanic Clouds (LMC and SMC) were simulated and then searched for pulsars. After accounting for the low escape velocities of both Clouds, the estimated birthrate of pulsars in either Cloud is 0.5--1.0 pulsars per century, and the estimated numbers of normal pulsars are (1.79 +/- 0.20) x 104 and (1.09 +/- 0.16) x 10 4 for the LMC and SMC, respectively. For the MSP populations, upper limits of 15,000 and 23,000 for the LMC and SMC were obtained. The SMC simulations predicted that up to three MSPs could be detected in a new, high-resolution survey performed at the Parkes Telescope in Parkes, Australia.;The pulsar search procedure is mostly computerized and is very data intensive. Fourier transforms are utilized in the search for periodic signals, and matched filtering is used to search for single bursts of radio emission. Acceleration searches attempt to find pulsars that are locked in binary orbits with other stars in which the pulsars' accelerations significantly affect the timing of the signals that telescopes on the Earth detect. These search techniques were applied to a survey for pulsars in the SMC that was executed at the Parkes Telescope in Parkes, Australia. This survey has, to date, redetected three known pulsars, discovered three potential MSP candidates, and placed an upper limit of 15 bursting sources in the SMC. The results of this survey have now led to a similar survey of the Large Magellanic Cloud that is currently in progress.

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