Pre-burst neutrinos of gamma-ray bursters accompanied by high-energy photons

Abstract

Previous researches on high-energy neutrino events from gamma-ray bursters (GRBs) suggest a neutrino speed variation $v(E)=c(1\pm E/E_{\mathrm{LV}}^{\nu })$ with $E_{\mathrm{LV}}^{\nu }=(6.4\pm 1.5)\times 10^{17}\mathrm{GeV}$, together with an intrinsic time difference $\Delta t_{\mathrm{in}}=(-2.8\pm 0.7)\times 10^2\mathrm{s}$, which means that high-energy neutrinos come out about 300~s earlier than low-energy photons in the source reference system. Considering the possibility that pre-bursts of neutrinos may be accompanied by high-energy photons, in this work we search for high-energy photon events with earlier emission time from 100 to 1000~s before low-energy photons at source by analyzing Fermi Gamma-ray Space Telescope (FGST) data. We perform the searching of photon events with energies larger than 100~MeV, and find 14 events from 48 GRBs with known redshifts. Combining these events with a $1.07\mathrm{TeV}$ photon event observed by the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC), we suggest a pre-burst stage with a long duration period of several minutes of high energy neutrino emissions accompanied by high energy photons at the GRB source.

Comments: 7 latex pages, 1 figure, final version for publication