Gamma-ray Bursts:Time Dependent Parameter Extension On The Shock Model Of The Afterglows And The EEP Test

Gamma-ray bursts(or GRBs)and their afterglows are important astronomical phenomena.With studing them,we can improve our understanding of the categories of astrophysical phenomena and processes,such as the center engine,active galactic nuclei(AGN),in which physical mechanisms have similarities.And,we can use GRBs to test basic physics theories(e.g.,general relativity and cosmology).Gamma ray bursts and their afterglows research involves many physical mechanism,such as radiation mechanism,fluid mechanics,the shock acceleration electrons,beaming,and so on.To study its physical model,we need not only the numerical simulation,but also algebra calculation,while the traditional manual calculation is becoming more and more difficult.Thanks to the progress of computer science,we now can use symbolic computation system to solve it.The thesis contains gamma critical afterglow time-dependent parameter extension of the standard model and a related application,namely testing Einstein's equivalence principle(EEP)with polarized gamma-ray bursts.The characteristics of the thesis are:(1)To illustrate the physical concepts and models,we take a minimal set of physical concepts to make it easier to understand;(2)The calculation have been simplified and the the physical images have been highlighted;(3)Maple as a computer algebra system is introduced as our working procedure(see appendix 2).Based on above,we strive to provide a usful framework.In Chapter 1,we do a summary of the observational characteristics of the gamma-ray burst,the internal and external shock model of gamma-ray bursts,and the standard model of GRB afterglows.In Chapter 2,we describe the physical mechanism of project related,such as spherically symmetric ideal fluid dynamics,shock wave,synchrotron radiation,inverse Compton scattering(IC),and post Newtonian approximation(PPN).Our purpose is to set a foundation for subsequent chapters.In Chapter 3,we revisit the GRB afterglows with time-dependent parameters.The work based on a set of general dynamics and radiation formulas by making four parameters dependent on time.As analysis formula,our results have the advantage-it is easy to find the inherent regularity.For example,we find that,at certain frequencies,radiation flux density does not depend on specific number density and the density profile of the environmental.In Chapter 4,we test the Einstein's equivalence principle with polarized gamma-ray bursts.We put forward a new method of limiting PPN parameter ?.Using linearly polarized GRBs,we export a restriction,which is more restricted than before by 12 orders of magnitude.The new method not only can be applied to other kinds of sources,but also can be used to design an experiment.In Chapter 5,we do a summary and outlook,including several ideas related to our subject for further research.In Appendix,we introduce Maple code of the GRB afterglows and the method of solving differential equations,including the similar variable method.