| After the discovery of the millisecond pulsars the model of a highly relativistic neutron star (NS) became the most acceptable to explain the observed pulses. Also, the discovery of sub-millisecond pulsar is expected. In this thesis, we study the effect of the gravitational mass of a pulsar on the amount of the electromagnetic radiation by using both the special and general theories of relativity. Relying on the magnetic dipole model of the pulsar, we use the extension of the work of Haxton-Ruffini [31] for single charges by DePaolis-Ingrosso-Qadir [32] for an obliquely rotating magnetic dipole, to incorporate the effect of the gravitational mass.;By using the numerical (evaluated by Mathematica 4.1) and analytical solutions of the differential equation for the radiation, we construct the energy spectra for different masses of the dipole. These spectra show that, in relatively low angular momentum l, the effect of the gravitational mass is very significant in suppressing the relativistic enhancement factor (gamma4), which had been found [27, 28, 32], by two orders of magnitude, as the mass changes from 0.5 M⊙ to 3 M⊙ . It is an indication that most of the angular momentum of the NS is retained as rotational kinetic energy instead of being radiated as an electromagnetic energy, E. Also, the suppressing in radiation energy is more or less independent of the angular momentum, l, and the high rotational velocity, beta. We also found that E ∼ o 4 sin2chi, where chi is the inclination angle of the obliquity, and o is the angular frequency of the dipole. It is similar to the classical behavior. However, in the very high l, the whole radiation suppresses and the effect of mass is neglected. It indicates that the (special) relativistic enhancement expected is lost to the (general) relativistic increase of angular momentum after incorporating the effect of mass. |
