Research Of Multi-component Gaussian Fitting And Spectral Index Of Integrated Pulsar Profiles

The research of radiation mechanism of pulsars is a very interesting subject. There are many methods to investigate this problem. But so far, it is still not fully understood. One of the important methods is using spectral index of integrated pulsar profiles to research possible radiation mechanisms. An integrated pulsar profiles is sum of many single pulses in cycle of the pulsar period. Usually an integrated pulsar profile can be separated in some Gaussian components. We can fit it by Gaussian function. Spectral index is the relationship between the observing frequency and flux intensity. We can understand some knowledge of the radiation mechanism by it. In this paper, we use the data from the European Pulsar Network. We fit the integrated pulsar profiles by Gaussian fitting and calculate spectral index of each component and profile. The main purpose of this article is to analysis possible radiation mechanism by spectral index. We can analysis whether the spectral index of each component is same as of total profile or not. We can verify that the radiation mechanism of each component is the same or not. The main contents of this article as the followings:The basic background knowledge of pulsar, research history and motivation of this research are shown in Chapter 1. The data and processing are introduced in Chapter 2. The result of our Gaussian fitting for each of choosing pulsars, the spectral index of each component and total profile are presented in Chapter 3.We have analysis integrated pulsar profile and the properties of the spectral index of each pulsar. The statistically research of spectral index is shown in Chapter 4. For spectral index of total profile, spectral index of 14.8% of pulsars is less than -2; 74.1% is between -2 to -1; 11.1% is between -1 to 0. Some other pulsar spectral index is turn-over. The spectral index can be divided into several categories:very steep spectrum; flat spectrum sources and turn-over spectrum. We analysis the statistical characteristics of spectral index of each component and total profile, we found the distribution of them are consistent with each other. We also found that when the spectral index of pulsars are between-2 to-1. more than half of them have different spectral index for each component. This mean the mechanism of each component may be different. Spectral index of each component is consistent with each other, when spectral index is very steep or flat, but we should point out that the sample of these two kinds of pulsars is small. The summary and outlook of this article are given in Chapter 5.