Are we making progress in finding the sources of the most energetic cosmic rays?

There is progress, in the sense that although the energies assigned to cosmic rays by air shower arrays may need reducing by about 20%, energy measurements are consistent at about this level, and several experiments now accord with a spectrum which astonishingly shows no GZK cut-off near 10²⁰eV, greatly limiting the possible source regions. The simplest interpretation is that few cosmic rays above 10¹⁹eV come from hundreds of Mpc, contrary to expectation on geometrical grounds. Most of the arrival directions of showers above 4x10¹⁹eV show little correlation with the supergalaxy or with matter concentrations within 200Mpc. The implications of the spectrum and the arrival directions are discussed. The most likely explanations of their unexpected features are either (a) that these cosmic rays come mainly from the decay of cosmological relic particles clustered in a large galactic halo (though not if photons really do form a large part of the decay spectrum), or (b) that local intergalactic magnetic fields are unexpectedly strong, and disguise the position of and enhance one extraordinary source within a few Mpc, or (c) most particles above 10¹⁹eV are very different from protons after all, and do not have a threshold for serious energy loss as low as 10²⁰eV, or (d) that there is a conspiracy of matching fluxes, so that most cosmic rays above 10¹⁹eV are from widespread extragalactic sources, but a superimposed hard spectrum from decaying halo relic particles neatly reduces the magnitude of the GZK fall-off above 10²⁰eV. Several close pairs of arrival directions may yet turn out to be accidental, but if not, explanations (a) and (b) fail. There are several diagnostic tests to be made by the well-placed first (Southern) Auger Project detector and the High-Resolution Fly's Eye detector.