| Cosmic Rays(CRs)are the charge particles from the outside of our solar sys-tem.Since its discovery in 1912,their origin is a mystery.The secondary high-energy photons and neutrinos would be produced via interaction between CRs and ambient during CRs’ propagation,thus the high-energy photons,high-energy neutrinos and high-energy CRs show strong physical relations.Supernova remanents(SNRs)in star-forming galaxy,tidal disruption events(TDEs),active galactic nucleus(AGNs)and so on are proposed as the CRs sources.Thanks to the Fermi mission for its fruitful GeV observations,now we can make some direct study on CRs particle acceleration mech-anism and radiation mechanism.The spectra of the Galactic SNR IC 443 and W 44 show the characteristic pion-decay signature,which give a direct proof of SNRs as the CRs accelerator.Meanwhile,IceCube telescope at the South Pole has detected dozens of high-energy neutrinos at TeV-PeV energy band and open the new era of the high-energy neutrino astronomy,but their origin and the correlation with ultra high-energy cosmic-ray are still unknown.The dissertation tries to find the GeV signals from star-forming galaxies(Arp 220 and LMC),TDEs and related with the ICeCube neutrinos to explore the CRs physics.In Chapter one,we give a brief introduction on CRs,the γ-Ray observation his-tory and radiation mechanism,and Fermi mission.In Chapter two,using the latest PASS 8 data of Fermi,we discover the high-energy emission from the nearby Ultra-Luminous Infrared Galaxy(Arp 220)for the first time,and confirm that the high-energy GeV emission should be due to the interaction between CRs and the ambient.Then we calculate directly the efficiency of supernova remnant accelerating CRs for the first time based on the γ-ray data,about 5%.In Chapter three,we make data analysis at the Large Magellanic Cloud(LMC)region with Fermi,and try to find the characteristic pion-decay signature.We find that the spectrum of LMC disk shows break at around～500 MeV.pp collision could explain the observation results,though the bremsstrahlung mechanism is not ruled out completely.In Chapter four,we search for the high-energy emission from three TDEs with relativistic jets(Swift J16444+5713,J2058.4+0516 and J1112.2-8238)observed by Swift and one nearby normal TDE(ASASSN-14li),and obtain the upper limit fluxes.The GeV emission fluxes at the flare states for the three Swift jetted TDEs are at least 100 times lower than that of KeV-MeV emission.Assumption that the depth of GeV is larger than unit,we obtain the upper limits of Lorentz factor for their jets.In Chapter five,we search for high-energy electromagnetic counterparts accompanying IceCube high-energy track-like neutrinos.Neither new GeV or X-Ray transient sources or flux increment of known sources related with IceCube neutrinos are found during the neutrinos detec-tion time,and only upper limit fluxes are given.We constrain the source number den-sity for high-energy neutrinos with these upper limit fluxes under some assumptions:star-forming galaxies satisfy our constraint in a large parameter space,and Long Gamma-Ray Bursts(LGRBs)can not act as the main contribution to produce these high-energy neutrinos.In the final chapter,we give some discussion and expectation. |
