130 research outputs found

    Gamma Ray Bursts in the Swift-Fermi Era

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    Gamma-ray bursts (GRBs) are among the most violent occurrences in the universe. They are powerful explosions, visible to high redshift, and thought to be the signature of black hole birth. They are highly luminous events and provide excellent probes of the distant universe. GRB research has greatly advanced over the past 10 years with the results from Swift, Fermi and an active follow-up community. In this review we survey the interplay between these recent observations and the theoretical models of the prompt GRB emission and the subsequent afterglows.Comment: 16 pages and 15 figures. Invited review article to appear in the special issue of Frontiers of Physics on High Energy Astrophysics, eds. B. Zhang and P. Meszaro

    Searches for sterile neutrinos with IceCube DeepCore

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    We show that study of the atmospheric neutrinos in the 10--100 GeV energy range by DeepCore sub-array of the IceCube Neutrino Observatory can substantially constrain the mixing of sterile neutrinos of mass 1\sim 1 eV with active neutrinos. In the scheme with one sterile neutrino we calculate νμ\nu_\mu- and νˉμ\bar{\nu}_\mu- oscillation probabilities as well as zenith angle distributions of νμCC\nu_\mu^{CC} events in different energy intervals in DeepCore. The distributions depend on the mass hierarchy of active neutrinos. Therefore, in principle, the hierarchy can be identified, if νs\nu_s exists. After a few years of exposure the DeepCore data will allow to exclude the mixing Uμ420.02|U_{\mu 4}|^2 \geq 0.02 indicated by the LSND/MiniBooNE results. Combination of the DeepCore and high energy IceCube data will further improve sensitivity to νs\nu_s mixing parameters.Comment: PDFLaTeX, 6 pages, 6 PDF figures, minor comments added, accepted in Phys. Rev.

    High Energy Neutrinos from Novae in Symbiotic Binaries: The Case of V407 Cygni

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    Detection of high-energy (~> 100 MeV) gamma rays by the Fermi Large Area Telescope (LAT) from a nova in the symbiotic binary system V407 Cygni has opened possibility of high-energy neutrino detection from this type of sources. Thermonuclear explosion on the white dwarf surface sets off a nova shell in motion that expands and slows down in a dense surrounding medium provided by the red giant companion. Particles are accelerated in the shocks of the shell, and interact with surrounding medium to produce observed gamma rays. We show that proton-proton interaction, which is most likely responsible for producing gamma rays via neutral pion decay, produces ~> 0.1 GeV neutrinos that can be detected by the current and future experiments at ~> 10 GeV.Comment: 5 pages, 2 figures, expanded discussion on detectability, accepted for publication in Phys. Rev.