Distribution And Radiation Mechanism Of High-energy Particles In Pulsar Wind Nebulae

More and more pulsar wind nebulae(PWNe)are detected in X-ray and gamma-ray bands with operations of new high-energy observatories.Termination shock waves,which accelerate electrons/positrons to relativistic energies,exist around high-speed stel-lar winds of the pulsars.These energetic electrons are injected into the surrounding medi-um to form PWNe,which emit non-thermal radiation from radio emission to gamma-rays.In this paper,we first collected the observed multiband radiation fluxes of many PWNe,and then studied the radiation properties of them by calculating the multiband radiation spectra.In the calculation process,the Markov Chain Monte Carlo(MCMC)method was used to limit the parameters,and the distribution law of high-energy particles in the PWNe can be investigated.Firstly,assuming that the high-energy electrons in the PWNe have a broken power-law spectral distribution,these electrons can generate multi-band radiation through synchrotron radiation and inverse Compton scattering,and,with the exception of an individual source,the observed spectra can be explained with an Exponential Cutoff Broken Power Law model.Secondly,we used the MCMC method to limit the distribution parameters of high-energy particles of 20 PWNe,and studied the statistical relationship between these parameters and the corresponding pulsar parameters and the age of the nebulae.The results show that the magnetic field strength are inversely related to the age of the nebulae,but it is positively related to the luminosity of the pulsar;moreover,the break energy Eb is positively correlated with the age of PWNe.Both the Cutoff energy E,and the electron energy We are positively correlated with the luminosity of the pulsars.(3)For G21.5-0.9,in addition to the electrons with break power law distribution,a new electron component should be added to explain the newly detected X-ray fluxes by Hitomi.