Black holes are one of the most fascinating predictions of general relativity. They are the natural product of the complete gravitational collapse of matter and today we have a body of observational evidence supporting the existence of black holes in the Universe. However, general relativity predicts that at the center of black holes there are spacetime singularities, where predictability is lost and standard physics breaks down. It is widely believed that spacetime singularities are a symptom of the limitations of general relativity and must be solved within a theory of quantum gravity. Since we do not have yet any mature and reliable candidate for a quantum gravity theory, researchers have studied toy-models of singularity-free black holes and of singularity-free gravitational collapses in order to explore possible implications of the yet unknown theory of quantum gravity. This book reviews all main models of regular black holes and non-singular gravitational collapses proposed in the literature, and discuss the theoretical and observational implications of these scenarios.

This book provides a comprehensive introduction to X-ray and gamma-ray astronomy. The first part discusses the basic theoretical and observational topics related to black hole astrophysics; the optics and the detectors employed in X-ray and gamma-ray astronomy; and past, present, and future X-ray and gamma-ray missions. The second part then describes data reduction and analysis, the statistics used in X-ray and gamma-ray astronomy, and demonstrates how to write a successful proposal and a scientific paper. Data reduction in connection with specific X-ray and gamma-ray missions is covered in the appendices. Presenting the state of the art in X-ray and gamma-ray astronomy, this is both a valuable textbook for students and an important reference resource for researchers in the field.

This book provides a comprehensive introduction to X-ray and gamma-ray astronomy. The first part discusses the basic theoretical and observational topics related to black hole astrophysics; the optics and the detectors employed in X-ray and gamma-ray astronomy; and past, present, and future X-ray and gamma-ray missions. The second part then describes data reduction and analysis, the statistics used in X-ray and gamma-ray astronomy, and demonstrates how to write a successful proposal and a scientific paper. Data reduction in connection with specific X-ray and gamma-ray missions is covered in the appendices. Presenting the state of the art in X-ray and gamma-ray astronomy, this is both a valuable textbook for students and an important reference resource for researchers in the field.

Following the approach of Lev Landau and Evgenii Lifshitz, this book introduces the theory of special and general relativity with the Lagrangian formalism and the principle of least action. This method allows the complete theory to be constructed starting from a small number of assumptions, and is the most natural approach in modern theoretical physics. The book begins by reviewing Newtonian mechanics and Newtonian gravity with the Lagrangian formalism and the principle of least action, and then moves to special and general relativity. Most calculations are presented step by step, as is done on the board in class. The book covers recent advances in gravitational wave astronomy and provides a general overview of current lines of research in gravity. It also includes numerous examples and problems in each chapter.

This book discusses the state of the art of the basic theoretical and observational topics related to black hole astrophysics. It covers all the main topics in this wide field, from the theory of accretion disks and formation mechanisms of jet and outflows, to their observed electromagnetic spectrum, and attempts to measure the spin of these objects. Black holes are one of the most fascinating predictions of general relativity and are currently a very hot topic in both physics and astrophysics. In the last five years there have been significant advances in our understanding of these systems, and in the next five years it should become possible to use them to test fundamental physics, in particular to predict the general relativity in the strong field regime. The book is both a reference work for researchers and a textbook for graduate students.

This book discusses the state of the art of the basic theoretical and observational topics related to black hole astrophysics. It covers all the main topics in this wide field, from the theory of accretion disks and formation mechanisms of jet and outflows, to their observed electromagnetic spectrum, and attempts to measure the spin of these objects. Black holes are one of the most fascinating predictions of general relativity and are currently a very hot topic in both physics and astrophysics. In the last five years there have been significant advances in our understanding of these systems, and in the next five years it should become possible to use them to test fundamental physics, in particular to predict the general relativity in the strong field regime. The book is both a reference work for researchers and a textbook for graduate students.