ﻻ يوجد ملخص باللغة العربية
We study the extragalactic protons with universal spectrum, which is independent of mode of propagation, when distance between sources is less than the propagation lengths, such as energy attenuation length or diffusion length (for propagation in magnetic fields). The propagation features in this spectrum, the GZK cutoff, dip and bump, are studied with help of modification factor, which weakly depends on the generation spectrum index $gamma_g$. We argue that from the above features the dip is the most model-independent one. For the power-law generation spectrum with $gamma_g=2.7$ the dip is very well confirmed by the data of all existing detectors, which gives the strong evidence for extragalactic protons propagating through CMB. We develop the AGN model for origin of UHECR, which successfully explains the observed spectra up to $1times 10^{20}$ eV and transition from galactic to extragalactic cosmic rays. The calculated spectrum has the GZK cutoff, and the AGASA excess of events at $E gsim 1times 10^{20}$ eV needs another component, e.g. from superheavy dark matter. In case of weak extragalactic magnetic fields this model is consistent with small-angle clustering and observed correlation with BL Lacs.
We briefly describe the energy loss processes of ultrahigh energy protons, heavier nuclei and gamma rays in interactions with the universal photon fields of the Universe. We then discuss the modification of the accelerated cosmic ray energy spectrum
We discuss the basic difficulties in understanding the origin of the highest energy particles in the Universe - the ultrahigh energy cosmic rays (UHECR). It is difficult to imagine the sources they are accelerated in. Because of the strong attenuatio
More than 100 years after the discovery of cosmic rays and various experimental efforts, the origin of ultra-high energy cosmic rays (E > 100 PeV) remains unclear. The understanding of production and propagation effects of these highest energetic par
The propagation trajectories of ultra-high-energy cosmic rays (UHECRs) are inevitably affected by Galactic magnetic field (GMF). Because of the inevitability, the importance of the studies of the propagation in GMF have increased to interpret the res
The origin of the ultra high energy cosmic rays (UHECR) with energies above E > 1017eV, is still unknown. The discovery of their sources will reveal the engines of the most energetic astrophysical accelerators in the universe. This is a written versi