TeV-PeV Neutrinos from Giant Flares of Magnetars and the Case of SGR 1806-20

We estimate the high-energy neutrino flux from the giant flare of SGR 1806-20 on A 2004 December 27, which irradiated Earth with a gamma-ray flux ~10^4 times larger than the most luminous gamma-ray bursts (GRBs) ever detected. The Antarctic Cerenkov neutrino detector AMANDA was online during the flare and may either have detected high-energy neutrinos for the first time from a cosmic point source or put constraints on the flare mechanism of magnetars. If TeV neutrinos are detected, one would also expect detectable EeV cosmic rays and possibly TeV gamma-ray emission in coincidence.