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.

The universe is pervaded by particles with extreme energies, millions of times greater than we can produce on Earth. They have been a mystery for over a century. Now, current and future experiments in particle astrophysics are leading us to answers to the most fundamental questions about them. How does nature accelerate the highest energy particles in the universe? Do new interactions between them occur at such extreme energies? Are there unknown aspects of spacetime that can be uncovered by studying these particles?This book brings together three fields within 'extreme astronomy': ultra-high-energy cosmic ray physics, neutrino astronomy, and gamma-ray astronomy, and discusses how each can help answer these questions. Each field is presented with a theoretical introduction that clearly elucidates the key questions scientists face. This is followed by chapters that discuss the current set of experiments — how they work and their discoveries. Finally, new techniques and approaches are discussed to solve the mysteries uncovered by the current experiments.

The research program in gamma-ray astronomy focuses on increasing our knowledge of the nature and origin of galactic and extragalactic gamma rays, and understanding high-energy processes in the Sun, celestial objects, interstellar medium, and extragalactic space.This book not only provides an overview of the latest research and future plans for space-borne and ground-based experiments dedicated to the observation of the gamma-ray sky, but also addresses the topic of variable gamma-ray sources from the perspective of their identification and counterparts at different wavelengths. It further gives an overview of the theory related to the most qualified emission processes that take place in these sources and of the nature of their variability.

Very-high-energy astrophysics studies the most energetic photons in the sky, allowing the exploration of violent and extreme non-thermal phenomena in the Universe. Significant advances in knowledge have been made in this field using ground-based imaging atmospheric Cherenkov telescopes (IACTs) as detectors, to study these physical processes in the Universe. This book reviews the progress in the field since the advent of the second generation IACTs around 2004. Going through the scientific highlights obtained by the three current instruments of this kind, H.E.S.S., MAGIC and VERITAS, operating now for more than 15 years, this book presents a state-of-the-art knowledge in four areas of modern astrophysics and cosmology, namely the origin of the cosmic rays, the physics of compact objects and their resulting relativistic outflows, gamma-ray cosmology, and the search for dark matter. Along with a detailed review of the outstanding scientific outcomes, a summary of the key technological developments that yielded the recognized success of the technique is also provided.This book is written for early-career academics in the fields of astrophysics, high energy physics and cosmology. At the same time, it can serve as a source of reference for the expert in the field.

This book provides the first comprehensive historical account of the evolution of scientific traditions in astronomy, astrophysics, and the space sciences within the Max Planck Society. Structured with in-depth archival research, interviews with protagonists, unpublished photographs, and an extensive bibliography, it follows a unique history: from the post-war relaunch of physical sciences in West Germany, to the spectacular developments and successes of cosmic sciences in the second half of the 20th century, up to the emergence of multi-messenger astronomy. It reveals how the Society acquired national and international acclaim in becoming one of the world’s most productive research organizations in these fields.

The proceedings of MG16 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 46 plenary presentations, 3 public lectures, 5 round tables and 81 parallel sessions arranged during the intense six-day online meeting. All talks were recorded and are available on the ICRANet YouTube channel at the following link: www.icranet.org/video_mg16.These proceedings are a representative sample of the very many contributions made at the meeting. They contain 383 papers, among which 14 come from the plenary sessions.The material represented in these proceedings cover the following topics: accretion, active galactic nuclei, alternative theories of gravity, black holes (theory, observations and experiments), binaries, boson stars, cosmic microwave background, cosmic strings, dark energy and large scale structure, dark matter, education, exact solutions, early universe, fundamental interactions and stellar evolution, fast transients, gravitational waves, high energy physics, history of relativity, neutron stars, precision tests, quantum gravity, strong fields, and white dwarf; all of them represented by a large number of contributions.The online e-proceedings are published in an open access format.

e-ASTROGAM (enhanced ASTROGAM) is a breakthrough Observatory space mission dedicated to the study of the Universe using gamma-rays in the mostly unexplored and crucial MeV-GeV energy range. e-ASTROGAM has been proposed for the ESA M5 mission. Thanks to its performance in the MeV-GeV domain, substantially improving its predecessors, e-ASTROGAM will open a new window on the non-thermal Universe, making pioneering observations of the most powerful Galactic and extragalactic sources. e-ASTROGAM will also determine the origin of key isotopes fundamental for the understanding of supernova explosion and the chemical evolution of our Galaxy. e-ASTROGAM has already collected the interest of more that 350 scientists from 19 different countries. About 100 scientists met in Padua from February 28 to March 2, 2017, to discuss some of the more relevant scientific aspects of the mission. This book collects their contributions.