| Several millisecond pulsars separated by large angles on the sky are used to construct a spatial Pulsar Timing Array (PTA). Correlations in the pulsar timing residuals can be caused by (1) reference clock wandering, (2) uncorrected perturbations in the Earth's orbit, (3) local deviations in the space-time metric, and (4) dispersion measure fluctuations. In this thesis I explore the PTA concept with regard to a timing program established at the National Radio Astronomy Observatory's 43 m telescope in Green Bank. Currently there are four pulsars included in the timing array: PSR's 1620-26, 1821-24, 1855+09, and 1937+21. The influences of global parameters--clock, Earth, and metric perturbations--on our data are discussed.; Results from two pulsar timing programs conducted at the National Radio Astronomy Observatory in Green Bank, West Virginia are presented. The first program covers observations between July 1987 and June 1989, while the second program covers observations between August 1989 and September 1990. The hardware used to collect the data are described. Estimates of the flux density and spectral indices of the four millisecond period radio pulsars are presented, including a derived analytic pulse template model based on a multi-frequency observing campaign conducted in August 1989. An assessment of the sources of uncertainty in the data is given, along with methods for improving data quality and array performance through future upgrades. Finally, a proposal is made for linking together pulsar data sets from different observatories by properly referencing pulse arrival times to a proper fiducial point. |
