Population Synthesis Of Pulsars In The Milky Way

Neutron star has been known as a very compact star with a density of up to 10¹⁵g/cm³,which is mainly composed by neutron.Neutron star usually have the characteristics of strong magnetic fields(about 10^8-15G)and short periods(about 0.001-10s),and a rapidly rotating and highly magnetized neutron star is called a pulsar.One of unknown question of the pulsar is the radio emission process.In particular,what is the maximum age of the pulsar that can emit the radio emission(so called death line in period()and period derivative#?$diagram)?The different emission processes predict the different death line,which is the related to the pair-creation process of the acceleration/emission region.With the current population of the radio pulsars,however,it is difficult to the identify the death-line on-?diagram.The current situation will be changed by the future Five-hundred-meter Aperture Spherical Telescope(FAST)observation.FAST can observe important part of the sky,including most of the Milky Way plane with unprecedent sensitivity.Hence FAST has great potential for finding many radio pulsars and for revealing observed“death-line”.This thesis focuses on the simulation study of the distribution of neutron stars/pulsars in the Milky Way.Using standard method for simulation of the radio pulsar,and predict the number of FAST observations.The previous population studies considered the pulsar age with less than about 5M years and neglected the evolution of the magnetic field.Our research work has made the following two improvements:(i)The first time considered the evolution of the magnetic field with age;(ii)We simulated pulsars less than 1000M years.Within the current framework,we find that the evolution of the magnetic field does affect to the results of the simulation,for example,the number of the detection of the pulsars.We also find that the physical death-line of the age which the pair-creation cannot be happen,is important to explain the age distribution of the currently known pulsars.Based on our simulation,we predict that FAST has a potential to detect about 7700 pulsars with its age less than 1000M years.As we expect,FAST will detect more new pulsars with a distance farther from the Earth and a lower luminosity.Our result suggests that with the significant increase of population of pulsars by FAST,FAST make a clear the observe“death-line”by significantly increase of population of pulsars,which advances the understanding of the radio emission mechanisms of the pulsars.The structure of the thesis is as follows:In the first chapter,we briefly introduced neutron stars and pulsars,and explained the purpose of this thesis;in the second chapter,we introduced the observations and theories of pulsars in detail,as well as the observations and theoretical studies of FAST;in the third chapter,we will introduce how to study the simulation of the pulsar in the Milky Way after considering the magnetic field decay and the"death line"correction;in the fourth chapter,we use this result to study FAST's estimated number of detected pulsars,as well as the potential research advantages of the radio radiation mechanism and the"death line"limit;in the fifth chapter,we summarize and look forward to the work.