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

We provide a comprehensive review of major developments in our understanding of gamma-
ray bursts, with particular focus on the discoveries made within the last fifteen years when …

The recent Fermi observation of GRB 080916C shows that the bright photosphere emission
associated with a putative fireball is missing, which suggests that the central engine likely …

Gamma-ray bursts (GRB's), short and intense pulses of low-energy γ rays, have fascinated
astronomers and astrophysicists since their unexpected discovery in the late sixties. During …

Gamma-ray bursts are the most luminous explosions in the Universe, and their origin and
mechanism are the focus of intense research and debate. More than three decades after …

Two types of gamma-ray bursts (GRBs) are observed: short-duration hard spectrum GRBs
and long-duration soft spectrum GRBs. For many years long GRBs were the focus of intense …

The afterglow emission from gamma-ray bursts (GRBs) is usually interpreted as synchrotron
radiation from electrons accelerated at the GRB external shock that propagates with …

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 …

Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary
in space physics and in astrophysics. They are to be found in a great variety of objects and …

Collisionless shocks can be produced as a result of strong magnetic fields in a plasma flow,
and therefore are common in many astrophysical systems. The Weibel instability is one …