It is common believe that the centers of all galaxies exhibit supermassive black holes with masses ranging from millions up to billions of the mass of our Sun. By accreting surrounding matter, the luminosity of these galactic nuclei can outshine the emission of their host galaxies. If this is the case, they are called active galactic nuclei. Some of these objects eject powerful outflows composed of plasma, called jets. These jets can produce non-thermal radiation which observable across the entire electromagnetic spectrum from radio up to the gamma-ray frequencies. At highest frequencies (TeV range) most of the detected active galaxies have jets directed along or close to the line of sight. However, also galaxies with larger angles to the line of sight showing fascinating features were discovered, in seeming contradiction to traditional models for these so-called radio galaxies. Thus, the latter are of particular importance for understanding active galactic nuclei in general. This Special Issue contains reviews and research articles about the current knowledge of radio galaxies at TeV energies, including observational results and theoretical models. It is intended to guide the interested reader deeper into this fascinating discipline of modern day astronomy.

Gamma ray astronomy, the branch of high energy astrophysics that studies the sky in energetic ?-ray photons, is destined to play a crucial role in the exploration of nonthermal phenomena in the Universe in their most extreme and violent forms. The great potential of this discipline offers impressive coverage of many OC hot topicsOCO of modern astrophysics and cosmology, such as the origin of galactic and extragalactic cosmic rays, particle acceleration and radiation processes under extreme astrophysical conditions, and the search for dark matter."

This book summarizes the science to be carried out by the upcoming Cherenkov Telescope Array, a major ground-based gamma-ray observatory that will be constructed over the next six to eight years. The major scientific themes, as well as core program of key science projects, have been developed by the CTA Consortium, a collaboration of scientists from many institutions worldwide.CTA will be the major facility in high-energy and very high-energy photon astronomy over the next decade and beyond. CTA will have capabilities well beyond past and present observatories. Thus, CTA's science program is expected to be rich and broad and will complement other major multiwavelength and multimessenger facilities. This book is intended to be the primary resource for the science case for CTA and it thus will be of great interest to the broader physics and astronomy communities. The electronic version (e-book) is available in open access.

A wide range of topics are covered, ranging from supernovae to active galactic nuclei, cosmic gamma rays to neutrinos and dark matter. The basic emphasis is on physics / astrophysics and experimental / observational techniques, scientific implications of current results, and prospects for future advances. The fields surveyed are in rapid development and the exploration of our high energy universe is proceeding rapidly, with exciting new discoveries. What unifies much of the new data is the idea of particle acceleration to enormous energies and the subsequent interactions of the particles with the local medium. It this focus that makes the book both timely and an important contribution to the field.

"I have taught from and enjoyed the first edition of the book. The selection of topics is the best I've seen. Maurizio Spurio gives very clear presentations using a generous amount of observational data. " James Matthews (Louisiana State University) This is the second edition of an introduction to “multi-messenger” astrophysics. It covers the many different aspects connecting particle physics with astrophysics and cosmology and introduces high-energy astrophysics using different probes: the electromagnetic radiation, with techniques developed by traditional astronomy; charged cosmic rays, gamma-rays and neutrinos, with methods developed in high-energy laboratories; and gravitational waves, recently observed using laser interferometers. The book offers a comprehensive and systematic approach to the theoretical background and the experimental aspects of the study of the high-energy universe. The breakthrough discovery of gravitational waves motivated this new edition of the book, to offer a more global and multimessenger vision of high-energy astrophysics. This second edition is updated and enriched with substantial new materials also deriving from the results obtained at the LIGO/Virgo observatories. For the first time it is now possible to draw the connection between gravitational waves, traditional astronomical observations and other probes (in particular, gamma-rays and neutrinos). The book draws on the extensive courses of Professor Maurizio Spurio at the University of Bologna and it is aimed at graduate students and post-graduate researchers with a basic understanding of particle and nuclear physics. It will also be of interest to particle physicists working in accelerator/collider physics who are keen to understand the mechanisms of the largest accelerators in the Universe.

This book, written by researchers who had been professionals in accelerator physics before becoming leaders of groups in astroparticle physics, introduces both fields in a balanced and elementary way, requiring only a basic knowledge of quantum mechanics on the part of the reader. The new profile of scientists in fundamental physics ideally involves the merging of knowledge in astroparticle and particle physics, but the duration of modern experiments is such that people cannot simultaneously be practitioners in both. Introduction to Particle and Astroparticle Physics is designed to bridge the gap between the fields. It can be used as a self-training book, a consultation book, or a textbook providing a “modern” approach to particles and fundamental interactions.

This book provides a theoretical and observational overview of the state of the art of gamma-ray astrophysics, and their impact and connection with the physics of cosmic rays and neutrinos. With the aim of shedding new and fresh light on the problem of the nature of the gamma-ray sources, particularly those yet unidentified, this book summarizes contributions to a workshop that continues today.