Related papers: The obscured gamma-ray and UHECR universe
We present a calculation of nuclei propagation with energies above 1 EeV in the intergalactic photon field. The calculation is based on a Monte Carlo approach for the nucleus-photon interaction as well as the intergalactic magnetic field.…
The detection of high-energy astrophysical multimessengers establishes a connection between ultra-high-energy cosmic rays (UHECRs) and powerful cosmic accelerators. Interactions of UHECRs with radiation fields and interstellar matter…
We measure the correlation between the arrival directions of the highest energy cosmic rays detected by the Pierre Auger Observatory with the position of the galaxies in the HI Parkes All Sky Survey (HIPASS) catalogue, weighted for their HI…
Recent observations with the Extreme Ultraviolet Explorer (EUVE) suggest that at least some clusters of galaxies are luminous sources of extreme ultraviolet (EUV) radiation. It is not clear yet whether EUV emission is a general feature of…
Ultra-high cosmic rays (UHECRs) with energies >10^19 eV emitted at cosmological distances will be attenuated by cosmic microwave and infrared background radiation through photohadronic processes. Lower energy extra-galactic cosmic rays…
We re-derive the possible dependence of the redshift with very high energy (VHE) $\gamma$-ray photon index. The results suggest that the universe to VHE $\gamma$-rays is becoming more transparent than usually expected. We introduce the…
The rarest cosmic rays above the GZK cut'off $(E_{CR} \tilde{>} 10^{19} \div 10^{20} eV)$ are probably born at cosmic distances ($\tilde{>}$ tens Mpc) by AGNs (QSRs, BLac, Blazars...). Their puzzling survival over $2.75 K^o$ BBR radio waves…
The origin and composition of Ultra-High Energy Cosmic Ray Events (UHECRs) are under debate. Here we improve constraints on the source population(s) and compositions of UHECRs by accounting for UHECR deflections within existing Galactic…
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…
The apparent lack of suitable astrophysical sources for cosmic rays with E > 10^{19.7} eV (UHECRs) is the "GZK Paradox". We argue that whatever mechanism produces them must also account for events down to ~10^{18.7} eV, including their…
The light emitted by stars and accreting compact objects through the history of the Universe is encoded in the intensity of the extragalactic background light (EBL). Knowledge of the EBL is important to understand the nature of star…
Earliest AUGER UHECR anisotropy correlated with AGN within a GZK Universe almost fade away. Recent UHECR mass compositions did show a negligible nucleon composition and an UHECR nuclei (light or heavy) signature. The absence of UHECR events…
The extragalactic background light (EBL) is all the electromagnetic energy released by resolved and unresolved extragalactic sources since the recombination era. Its intensity and spectral shape provide information about the evolution of…
Motivated by recent Pierre Auger result on the correlation of the highest-energy cosmic rays with the nearby active galactic nuclei, we explore possible ultrahigh energy cosmic ray (UHECR) source distributions and their effects on GZK…
Ultra High Cosmic Rays) made by He-like lightest nuclei might solve the AUGER extragalactic clustering along Cen A. Moreover He like UHECR nuclei cannot arrive from Virgo because the light nuclei fragility and opacity above a few Mpc,…
We outline two concepts to explain Ultra High Energy Cosmic Rays (UHECRs), one based on radio galaxies and their relativistic jets and terminal hot spots, and one based on relativistic Super-Novae (SNe) or Gamma Ray Bursts (GRBs) in…
The discovery of distant sources of very high energy (VHE) gamma-rays with hard energy spectra enabled to derive strong upper limits on the density of the extragalactic background light (EBL). These limits are close to the lower limits…
Detecting neutrinos and photons is crucial to identifying the sources of ultrahigh-energy cosmic rays (UHECRs), especially for transient sources. We focus on ultrahigh-energy gamma-ray emission from transient sources such as gamma-ray…
We propose that ultrahigh energy cosmic rays are produced in binary neutron star mergers. This scenario can account for the heretofore inexplicable narrow rigidity range of UHECRs, because the jets of BNS mergers are generated by a…
The sources of ultra-high energy cosmic rays (UHECRs) are still one of the main open questions in high-energy astrophysics. If UHECRs are accelerated in astrophysical sources, they are expected to produce high-energy photons and neutrinos…