Related papers: The Extreme Universe: Some Views From Here
Recent measurements of the properties of cosmic rays above 10^17 eV are summarized and implications on our contemporary understanding of their origin are discussed. Cosmic rays with energies exceeding 10^20 eV have been measured, they are…
One of the most striking astrophysical phenomena today is the existence of cosmic ray particles with energies in excess of 10^20 eV. While their presence has been confirmed by a number of experiments, it is not clear where and how these…
The highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic processes in the Universe. Their existence triggered a flurry of theoretical explanations ranging from…
The most energetic particles ever detected exceed $10^{20}$ eV in energy. Their existence represents at the same time a great challenge for particle physics and astrophysics, and a great promise of providing us for a probe of the validity…
In this chapter, we discuss the contributions of gamma-ray astronomy at TeV energies to our understanding of the visible content and structure of the universe. We start from the present epoch with the second most intense electromagnetic…
The field of high energy particle astronomy is exciting and rapidly developing. In the last few years, we have detected extragalactic sources of intense TeV gamma radiation and individual cosmic ray particles with energies exceeding 25…
This review summarizes recent developments in the understanding of high-energy cosmic rays. It focuses on galactic and presumably extragalactic particles in the energy range from the knee (10^15 eV) up to the highest energies observed…
Over the last third of the century, a few tens of events, detected by ground-based cosmic ray detectors, have opened a new window in the field of high-energy astrophysics. These events have macroscopic energies, unobserved sources, an…
The origin of cosmic rays is one of the major unresolved questions in astrophysics. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely associated with the most energetic processes…
More than 100 years after the discovery of cosmic rays and various experimental efforts, the origin of ultra-high energy cosmic rays (E > 100 PeV) remains unclear. The understanding of production and propagation effects of these highest…
A fundamental question that can be answered in the next decade is: WHAT IS THE ORIGIN OF THE HIGHEST ENERGY COSMIC PARTICLES? The discovery of the sources of the highest energy cosmic rays will reveal the workings of the most energetic…
An overview on the present observational status and phenomenological understanding of cosmic rays above 10^16 eV is given. Above these energies the cosmic ray flux is expected to be gradually dominated by an extra-galactic component. In…
Although cosmic rays were discovered 90 years ago, we do not know how and where they are accelerated. There is compelling evidence that the highest energy cosmic rays are extra-galactic -- they cannot be contained by our galaxy's magnetic…
In this review we discuss the important progress made in recent years towards understanding the experimental data on cosmic rays with energies $\agt 10^{19}$ eV. We begin with a brief survey of the available data, including a description of…
Ultrahigh energy cosmic rays are the most energetic of any subatomic particles ever observed in nature. The quest for their mysterious origin is currently a major scientific challenge. Here we explore the possibility that these particles…
Energetic particles, traditionally called Cosmic Rays, were discovered nearly a hundred years ago, and their origin is still uncertain. Their main constituents are the normal nuclei as in the standard cosmic abundances of matter, with some…
The experimental search for ultra high energy cosmic messengers, from $E\sim 10^{19}$ eV to beyond $E\sim 10^{20}$ eV, at the very end of the known energy spectrum, constitutes an extraordinary opportunity to explore a largely unknown…
Historically cosmic rays have always been at the intersection of astrophysics with particle physics. This is still and especially true in current days where experimenters routinely observe atmospheric showers from particles whose energies…
This article reviews the present status of high energy gamma-ray astronomy at energies above 30 MeV. Observations in the past decade using both space- and ground-based experiments have been primarily responsible for giving a tremendous…
The understanding of the nature of ultra-high-energy cosmic rays is one of the most intriguing open questions for current and future observatories. These particles are expected to be accelerated in extragalactic sources. Because of their…