Clustering properties of ultrahigh energy cosmic rays and the search for their astrophysical sources
The arrival directions of ultrahigh energy cosmic rays (UHECRs) may show anisotropies on all scales, from just above the experimental angular resolution up to medium scales and dipole anisotropies. We find that a global comparison of the two-point auto-correlation function of the data with the one of catalogues of potential sources is a powerful diagnostic tool. In particular, this method is far less sensitive to unknown deflections in magnetic fields than cross-correlation studies while keeping a strong discrimination power among source candidates. We illustrate these advantages by considering ordinary galaxies, gamma ray bursts and active galactic nuclei as possible sources. Already the sparse publicly available data suggest that the sources of UHECRs may be a strongly clustered sub-sample of galaxies or of active galactic nuclei. We present forecasts for various cases of source distributions which can be checked soon by the Pierre Auger Observatory.
- Research Organization:
- Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC02-07CH11359
- OSTI ID:
- 920440
- Report Number(s):
- FERMILAB-PUB-07-467-A; arXiv eprint number arXiv:0709.2712; TRN: US200818%%928
- Country of Publication:
- United States
- Language:
- English
Similar Records
On the Possible Association of Ultra High Energy Cosmic Rays with Nearby Active Galaxies
Radio-quiet active galactic nuclei as possible sources of ultrahigh-energy cosmic rays