Understanding the physical mechanisms that control galaxy formation is a fundamental
challenge in contemporary astrophysics. Recent advances in the field of astrophysical …

Radio observations prove the existence of relativistic particles and magnetic field associated
with the intra-cluster-medium (ICM) through the presence of extended synchrotron emission …

Galactic cosmic rays reach energies of at least a few petaelectronvolts (of the order of 1015
electronvolts). This implies that our Galaxy contains petaelectronvolt accelerators …

The present white paper is submitted as part of the “Snowmass” process to help inform the
long-term plans of the United States Department of Energy and the National Science …

We survey our understanding of classical novae—nonterminal, thermonuclear eruptions on
the surfaces of white dwarfs in binary systems. The recent and unexpected discovery of GeV …

Abstract One century ago Viktor Hess carried out several balloon flights that led him to
conclude that the penetrating radiation responsible for the discharge of electroscopes was of …

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs,
due to the accretion of fresh material from a binary companion. The shock generated when …

The origin of the highest energy cosmic rays is still unknown. The discovery of their sources
is expected to reveal the workings of the most energetic astrophysical accelerators in the …

A critical review of the standard paradigm for the origin of Galactic cosmic rays (CRs) is
presented. Recent measurements of local and far-away CRs reveal unexpected behaviors …

Supernova remnants are beautiful astronomical objects that are also of high scientific
interest, because they provide insights into supernova explosion mechanisms, and because …