Mapping the most energetic cosmic rays

Abstract

The correlation between the directions of optically-detected AGNs within 75 Mpc and the arrival directions of cosmic rays above 57 EeV detected by the Auger collaboration up to August 2007 is examined using uniform-exposure plots and a form of right ascension resonance which does not require choice of an association window radius. Using the latter, the chance of accidental correlation is found to be well below 1 in 10^5 even without using 3.2 degree windows; the correlation with FRI-like radio galaxies within 75 Mpc, listed by Nagar & Matulich (which are in AGN clusters), is separately just as significant; and a correlation can also be found in other data at a lower energy. Cen A is currently inactive at this energy, as more distant radio galaxies are so prominent. The efficacy of a 57 EeV cut to select this revelatory (proton) sample of the Auger data may be almost accidental and not robust. The cosmic rays in the Auger sample seem to be scattered by ~3-4 degrees en route, from about 50 Mpc, and in one relatively well probed sky region there may be a 4 degree systematic deflection in a Bz component of the magnetic field in the galactic halo. The sources appear to be mostly within 120 Mpc. This is compatible with a GZK survival horizon, but only if (a) the Auger energies are underestimated by ~25% and (b) the sudden fall in the energy spectrum is not simply a GZK effect but essentially reflects an energy cut-off in the sources.Comment: Submitted to Astroparticle Physics; 27 pages, 13 figures (20 panels

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

“…Moreover, active galaxies in this catalog trace the nearby large-scale matter distribution, and that includes all types of candidate astrophysical sources, not only AGNs and their subclasses. Analyses comparing the Auger data reported in [6,7] with different types of nearby extragalactic objects can be found in [12][13][14][15][16][17][18][19][20][21][22].…”

Centaurus A at Ultra-High Energies

“…This is due to its proximity to us, and it could be that some of the other objects are more effective at accelerating particles to the highest energies. We noted that Cen A may be a variable source at high energies, which may support this idea (Hillas 2009). …”

Gamma rays and neutrinos from a cosmic ray source in the Galactic Center region

“…[11]) by means of the first order Fermi mechanism. Also, the experimental evidence indicates that the injected composition of the Galactic sources is dominated by protons [12].…”