Constraint On The Parameters Of The Inverse Compton Scattering Model For Radio Pulsars

Pulsar is a kind of compact object which can produce periodical pulsed electromagneticemission. Its typical radius is about10km with a mass close to the sun. Pulsars have ex-tremely strong magnetic field, which can be as high as1014gauss. The rotating magnetic fieldleads to a strong electric field, accelerating electrons to highly relativistic energy. There areseveral theoretical models for possible acceleration region, say, inner vacuum gap model, slotgap model, outer gap model and annular gap model, in which the acceleration regions locateat different parts of pulsar magnetosphere. The radiation mechanism of relativistic chargedparticles in different acceleration regions may be various. At present, the possible radiationmechanism includes plasma’s emission, curvature radiation or inverse Compton scattering ofcharged particles.The inverse Compton scattering model (ICS) is mainly used to explain radiation of pulsarsat radio band. It assumes that low frequency electromagnetic wave (106Hz) is produced aroundthe neutron star due to the avalanche of the inner vacuum gap, besides, the cascade process pro-duces numerous of high-energy secondary pairs. Then the low-frequency wave will be scatteredby the secondary electrons, obtaining energy from the electrons and generating radio emission.In this work, the sample is composed of15pulsars, of which the profile widths graduallynarrow down as the frequency increase. By analyzing the profile data download from EuropeanPulsar Network(EPN), we measure the pulse widths of the pulsars and constrain the parameterspace of ICS model, i.e, the initial Lorentz factor γ0and the energy loss factor ξ of the sec-ondary electrons. The results show that electron Lorentz factor γ0>4000, which agrees with theprediction of the inner vacuum gap model; and the energy loss factor20<ξ <560, revealingthat there should exist certain energy loss mechanism to account for such a high energy loss.Chapter1and2introduces the background of pulsars research, say, its history, category,inner structure of neutron stars, observational characteristics, theoretical models and researchfronterier.Chapter3describes how to select samples from EPN database, and the two methods ofconstraining parameter space. Chapter4focuses on the results and the theoretical discussion.Chapter5gives a brief summary and prospect.