Gamma-Ray Burst Multi-Messenger Approach

Gamma-ray burst (GRB) are brief events occurring at the cosmological distance, in which photons with energies up to tens of GeV have been detected. The GRBs with GeV emission detected by Fermi LAT have three common features, which are, the distinct power-law spectral component, the delayed onset of high energy (GeV) emission and the long-lived high energy (GeV) emission. The high energy gamma-ray observations open a new window for GRB study. Also, GRBs are suggested to be the major sources of the ultra high energy cosmic rays (UHECRs), as a consequence, neutrino emission from GRBs are predicted. The observations of UHECRs by the Pierre Auger Observatory, in addition to the nondetection of GRB neutrinos from IceCube, can constrain the properties of GRBs, such as, the GRB generation rate, the luminosity, the bulk Lorentz factor. Thus, the detections on UHECRs and the high energy neutrinos provide two more channels to study GRBs. In this paper, we focus on the multi-messenger approach to study the origins of the GRB high energy photons and constrain the properties of GRBs.A brief review on the GRB high energy gamma-ray emission, the GRB high energy neutrino emission and the connection between UHECRs emission and GRBs is given in Chapter1. We first introduce the GRB study previous to Fermi Era and the standard fireball model. Secondly, we introduce the GRB observations from Fermi LAT and present the possible mechanisms for the high energy gamma-ray emission. We then introduce the high energy neutrino emission from GRBs. At last, we present the UHECRs observations and the requirements on GRBs under the assumption of GRBs as the major sources of UHECRs.In Chapter2, we study the origin of the long-lived high-energy (>100MeV) gamma-ray emission on the case of the short GRB090510, by using broad-band observations including X-ray and optical data. Under the constraints from the low-energy observations, the adiabatic forward shock synchrotron emission is consistent with the later-time (t>2s) high-energy observation, but falls below the early-time (t<2s) high energy observation. We attribute the early part of the high-energy emission (t<2s) to the prompt component, and the long-lived high energy emission (t>2s) to the adiabatic forward shock synchrotron afterglow radiation. In Chapter3, we study effects of the Klein-Nishina scattering on the high-energy synchrotron afterglow emission. We find that, at early times the Klein-Nishina suppression effect on those electrons that produce the high-energy emission is usually strong and therefore their inverse-Compton loss is small for a wide range of parameter space. This leads to a relatively bright synchrotron afterglow at high energies that can be detected by Fermi LAT. As the Klein-Nishina suppression effect weakens with time, the inverse-Compton loss increases and could dominate over the synchrotron loss in some parameter space. This will lead to a faster temporal decay of the high-energy synchrotron emission than what is predicted by the standard synchrotron model, which may explain the observed rapid decay of the early high-energy gamma-ray emission in GRB090902B.In Chapter4, we study the origin of the GeV emission during the X-ray flaring activity. GeV emission with a hard spectrum during the X-ray flaring activity has been detected for the first time by the Fermi/LAT in GRB100728A. We find that the hard spectrum of the GeV emission favors the external inverse-Compton origin in which X-ray flare photons are up-scattered by relativistic electrons in the external forward shock. This external inverse-Compton scenario, with anisotropic scattering effect taken into account, can reproduce the temporal and spectral properties of the GeV emission in GRB100728A.In Chapter5, we predict the high energy emission for the low luminosity GRBs in two scenarios, one of which is the conventional relativistic outflow with initial Lorentz factor of order of Г>10and the other of which is a trans-relativistic outflow with Г-1-2, taking into account both synchrotron self inverse-Compton scattering (SSC) and the external inverse-Compton scattering due to photons from the cooling supernova or hypernova envelope (SNIC). And we predict that the Fermi Gamma-ray Space Telescope may be able to detect the high energy emission from the low luminosity GRBs.In Chapter6, we show that the IceCube group used an overestimated theoretical flux in comparison with the IceCube instrument limit. We revisit the analytic calculation of the neutrino flux and consider the realistic photon energy distribution when calculating the number density of the fireball photons, and we also use the appropriate normalization for the proton flux to evaluate the neutrino flux. We calculate the theoretical neutrino flux from215bursts during the period of the40-string and59-string configurations of IceCube for benchmark model parameter, and find that it is a factor of-3below the IceCube sensitivity. We also adopt the recently found inherent relation between the bulk Lorentz factor and burst energy and constrain the baryon loading ratio by the nondetection of IceCube. We also calculate the diffuse neutrino flux from GRBs for different luminosity functions existing in literature, find that the expected flux exceeds the current IceCube limit for some luminosity functions and thus constrains the the baryon loading ratio.Our research prospects are given in Chapter7, we expect to study the connection between GRBs and the high energy cosmic rays via multi-messenger approaches.