Self-consistent And Time-dependent Lepto-hadronic Blazar Emission Model

The study of multi-band non-thermal emissions from blazars is an important issue in the physics of active galactic nuclei,and the origin of high-energy photons is not clear yet.In this thesis,the multi-band non-thermal emission from blazars,particularly that in high-energy region,is investigated.Main results of this thesis are as follows.A self-consistent and time-dependent lepto-hadronic model for blazar emission is set up.In this model,the evolution equations of protons,electrons,and non-thermal photons in a one-zone homogeneous jet model are simultaneously solved,and the phys-ical processes involved include proton-proton interactions,Bethe-Heitler pair produc-tion,proton-photon pion production,synchrotron radiation of protons and electrons,synchrotron self-absorption,Inverse Compton scattering,Compton scattering,photon-photon pair production,and electron-positron pair annihilation.The numerical method is given and numerical results are tested.Based on the lepto-hadronic model,a one-zone homogeneous self-consistent mod-el for the multi-band emission of PKS 1424+240,that allows the effects of automatic photon quenching to be studied,is presented.In the model,a steady y-ray injection rate in the source is assumed and the non-linear time-dependent kinematic equations describing evolution of both electrons and photons are acquired,these self-consistently involve photon-photon interaction,synchrotron radiation of electron/positron pairs,in-verse Compton scattering,and synchrotron self-absorption.The model is applied to reproduce the multiwavelength spectrum of PKS 1424+240;our results indicate that the observed spectral energy distribution(SED)of PKS 1424 + 240 can be reproduced well in the case of both electron injection and photon injection.The injected electrons mainly influence the SED over radio,optical and X-ray bands,and the SED at high energy y-ray band is mainly determined by the automatic photon quenching;in particular,the break form of the spectrum in the energy range of ? a few GeV is caused by this.It should be noted that the observed SED from X-ray to y-ray bands can be reproduced only through quenching,provided the observed data in the optical band are produced through some other mechanism,e.g.electron synchrotron radiation.The multi-band non-thermal emissions of two TeV blazars are studied in the lepto-hadronic model.Our results indicate that(1)non-thermal photons at optical and X-ray bands of PKS 2155-304 are contributed by synchrotron radiation of primary and secon-daries electron,y-rays are from synchrotron radiation of proton and secondaries elec-tron,particularly,the TeV bump of PKS 2155-304 at the energy range of E?2 × 106 MeV are contributed by the synchrotron radiation of secondaries electron which pro-duced by Bethe-Heitler pair production;(2)the multi-band non-thermal photon spec-trum of PG 1553+113 can be reproduced well.