We review open questions and prospects for progress in ultrahigh-energy cosmic ray
(UHECR) research, based on a series of discussions that took place during the “The High …

The search for Galactic pevatrons is now a well-identified key science project of all
instruments operating in the very-high-energy domain. Indeed, in this energy range, the …

We give a brief review of the origin and acceleration of cosmic rays (CRs), emphasizing the
production of CRs at different stages of supernova evolution by the first-order Fermi shock …

Observations of the Milky Way at TeV–PeV energies reveal a bright diffuse flux of hadronic
cosmic rays and also bright point sources of gamma rays. If the gamma-ray sources are …

The HAWC Collaboration has observed gamma rays at energies above 56 TeV from a
collection of nine sources. It has been suggested that this emission could be hadronic in …

We investigate acceleration and propagation processes of high-energy particles inside hot
accretion flows. The magnetorotational instability (MRI) creates turbulence inside accretion …

The IceCube Collaboration has published four years of data and the observed neutrino flux
is significantly in excess of the expected atmospheric background. Due to the steeply falling …

It is shown that the relativistic jets associated with the growth and past activity of the
supermassive black hole in the Andromeda galaxy could be the main source of cosmic rays …

High-energy neutrinos present the ultimate signature for a cosmic ray accelerator. Galactic
sources responsible for acceleration of cosmic ray up to the knee in cosmic ray spectrum will …

Diffuse TeV emission has been observed by HESS in the Galactic Center region, in addition
to the GeV gamma rays observed by Fermi. We propose that a population of unresolved …