Home
For authors
Submission status

Current
Archive (English)
Archive
   Volumes 61-80
   Volumes 41-60
   Volumes 21-40
   Volumes 1-20
   Volumes 81-92
      Volume 92
      Volume 91
      Volume 90
      Volume 89
      Volume 88
      Volume 87
      Volume 86
      Volume 85
      Volume 84
      Volume 83
      Volume 82
      Volume 81
Search
VOLUME 88 (2008) | ISSUE 9 | PAGE 643
The GZK horizon and constraints on the cosmic ray source spectrum from observations in the GZK regime
PACS: 98.70.Sa
Abstract
We discuss the GZK horizon of protons and present a method to constrain the injection spectrum of ultrahigh energy cosmic rays (UHECRs) from supposedly identified extragalactic sources. This method can be applied even when only one or two events per source are observed and is based on the analysis of the probability for a given source to populate different energy bins, depending on the actual cosmic ray injection spectral index. In particular, we show that for a typical source density of 4•10-5 Mpc-3, a data set of 100 events above 6•1019 eV allows one in 97% of all cases to distinguish a source spectrum dN/dE\propto E^{-1.1} from one with E-2.7 at 95% confidence level.