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P. W. Gorham (University of Hawaii at Manoa)
At photon energies above several tens TeV, extragalactic astronomy with photons is no longer viable. The only remaining stable messengers are charged particles and neutrinos. Yet we know that the spectral output of sources extend to at least 1020 eV because we observe cosmic rays up to these energies. Thus around 7 orders of magnitude of energetics in extragalactic sources remain unexplored. Telescopes for such energies must be physically enormous to achieve useful collecting areas. Costs for traditional particle detectors such as ring-imaging optical Cherenkov arrays grow too rapidly to scale to energies above 1 PeV. Radio detection provides an attractive alternative with tremendous potential for higher energies. We discuss here the basis for radio detection of both cosmic ray air showers (primarily through geosynchrotron emission) and neutrinos in solid dielectrics via the Askaryan effect. Several new projects, including the Antarctic Long Duration Balloon project ANITA, with an aperture of order 1M km2 , will be detailed.
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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.