Research On Problems Related To Neutron Stars And Gamma-ray Bursts

Gamma-ray bursts(GRB)are the most violent explosion in the Universe,and a powerful tool to probe the high-redshift Universe.Generally,GRBs can be classified as short GRBs(T<2 s)and long GRBs(T>2 s),according to the duration T.This paper will focus on the astrophysical phenomena related to the GRBs,based on the current good understanding of the astrophysical process in GRBs.I will summarize the current research progresses of GRBs' progenitors and their related transient phenomena in chapter 1.In chapter 2,as GRBs are the possible cosmic ray(CR)sources,I study the their high energy radiation(>GeV),which generated by the electromagnetic cascade in the magnetic field.The electrons(as the secondaries of CRs)in the GRB fireball can emit high-energy synchrotron photons,while these photons can be absorbed by the magnetic field to produce high-energy electron-positron pairs.Also I find a universal analytical expression for the photon spectrum in the cascade.In chapter 3,I will model the fast radio burst(FRB)with the coherent curvature radiation during the inspiral of double NSs.In the same time,the repeating FRB can be described by a similar model,namely the collision of a NS with an asteroid in an asteroid belt.While in chapter 4,I will study the high-energy radiation and possible EeV protons during the inspiral of double neutron stars(NSs),which is the progenitor of a short GRB.And then I will apply it to the precursors of short GRBs.It should be noted that the high-energy radiation has a wider opening angle than that of a FRB,and the pointed directions of GRBs,precursors and FRBs are different.Therefore,it is not likely that we can observe all components at the same time.In chapter 5,I will study the gravitational radiation from the possible central en-gine of a GRB-a hyper-critical accreting magnetar.The magnetar will radiate gravita-tional wave via generating the r-mode instability,while the produce toroidal magnetic field will suppress it.The gravitational wave signal is detectable only if it is close enough.And the gravitational radiation spins down the magnetar significantly,thus there can be some limitations to the super-luminous supernovae,since they may share the same central engine.The above researches are theoretical works,in the next chapters,I will introduce my work on data and statistics.In chapter 6,I will study the GRB cosmology,including using GRBs to constrain cosmological model,studying the possible anisotropic expan-sion of the Universe(significance level>2?),and studying the possible interaction between the dark matter and dark energy(significance level>2?).In chapter 7,I will study the self-organized criticality phenomenon and apply it on the type I X-ray bursts in low mass X-ray binaries.Also I will introduce the universal model of the waiting time distribution.Thanks to the new observatories in our country,such as FAST,HXMT,and DAMPE,and the international observatories,we can obtain more accurate data of these events,such as GRBs,supernovae,FRBs and so on.So we can perform further study on these transients and their relations,also we can constrain cosmological model tighter and probe the high-redshift Universe better.