1 research outputs found
Time Structure of Ultra-High Energy Cosmic Ray Sources and Consequences for Multi-messenger Signatures.
The latest results on the sky distribution of ultra-high energy cosmic ray
sources have consequences for their nature and time structure. If the sources
accelerate predominantly nuclei of atomic number A and charge Z and emit
continuously, their luminosity in cosmic rays above ~6x10^{19} eV can be no
more than a fraction of ~5x10^{-4} Z^{-2} of their total power output. Such
sources could produce a diffuse neutrino flux that gives rise to several events
per year in neutrino telescopes of km^3 size. Continuously emitting sources
should be easily visible in photons below ~100 GeV, but not in TeV gamma-rays
which are likely absorbed within the source. For episodic sources that are
beamed by a Lorentz factor Gamma, the bursts or flares have to last at least
~0.1 Gamma^{-4} A^{-4} yr. A considerable fraction of the flare luminosity
could go into highest energy cosmic rays, in which case the rate of flares per
source has to be less than ~5x10^{-3} Gamma^4 A^4 Z^2 yr^{-1}. Episodic sources
should have detectable variability both at GLAST and TeV energies, but neutrino
fluxes may be hard to detect.Comment: 6 pages, no figure