# Foundations of High-Energy Astrophysics

- Contents
- Review Quotes

**Preface**

**1 Hydrodynamics**

1.1 The Mass Conservation Equation

1.2 The Momentum Conservation Equation

1.3 The Energy Conservation Equation

1.4 Bernoulli’s Theorem

1.5 The Equations of Hydrodynamics in Conservative Form

1.6 Viscous Fluids

1.7 Small Perturbations

1.8 Discontinuity

1.8.2 ShockWaves

1.8.3 Physical Interpretation of Shock Waves

1.8.4 Collisional and Noncollisional Shocks

1.8.5 Formation of a Shock

1.10.2 The Strong Explosion

1.12 Problems

**2 Magnetohydrodynamics and Magnetic**

**Fields**

2.1 Equations of Motion

2.1.2 Equations of Motion in a Conservative Form

2.3 Magnetic Flux Freezing

2.4 Small Perturbations in a Homogeneous Medium

2.5 Stability of Tangential Discontinuities

2.6 Two-Temperature Fluids

2.7 Magnetic Buoyancy and Reconnection

2.7.2 Reconnection

2.9 Magnetic Fields in Astrophysics

2.9.2 Origin of Magnetic Fields

**3 Radiative Processes**

3.1 Radiative Transport

3.3 Bremsstrahlung

3.4 Synchrotron

3.4.2 The Spectrum of a Single Particle

3.4.3 The Spectrum of a Group of Nonthermal Particles

3.4.4 Quantum Corrections

3.4.5 Self-absorption

3.4.6 Cyclotron Lines

3.4.7 Processes in an Intense Magnetic Field

3.4.8 The Razin-Tsytovich Effect

3.5.2 The Spectrum of Inverse Compton Processes

3.5.3 About the Compton Parameter

3.5.4 Self-synchro-Compton and Compton Limit

3.5.5 Compton Broadening

3.6.2 Emission Properties of Relativistic Sources

3.8 Cosmological Attenuations

3.8.2 Photons

**4 Nonthermal Particles**

4.1 The Classic Theory of Acceleration

4.1.2 Injection

4.3 More Details in the Newtonian Limit

4.3.2 Scattering in the Angle of Motion in a Mediumat Rest

4.3.3 Scattering and Convection in a Mediumin Motion

*f*

4.4.2 The Small Pitch Angle Scattering Limit

4.4.3 Distributions of Probability

*P*u and

*P*d

4.4.4 The Particles’ Spectrum

4.4.5 The Equations for

*P*u and

*P*d

4.4.6 Results

4.6 Problems

**5 Spherical Flows: Accretion and Explosion**

5.1 Accretion from Cold Matter

5.2 Accretion from Hot Matter

5.4 Doubts about the Bondi Accretion Rate

5.5 The Eddington Luminosity

5.6 The Efficiency of Spherical Accretion

5.7 Explosive Motions

5.7.2 Gamma Ray Bursts

**6 Disk Accretion I**

6.1 Qualitative Introduction

6.2 Fundamental Equations

6.3 Special Relations

6.4 The

*α*Prescription

6.5 Equations for the Structure of Disks

6.6 The Standard Solution

6.7 The Origin of Torque

6.8 Disk Stability

6.8.2 Instability

6.10 Problems

**7 Disk Accretion II**

7.1 Other Disk Models

7.1.2 Dynamic Peculiarities of Pair Plasmas

7.1.3 The Pair Plasma without Input of External Photons

7.1.4 The Pair Plasma with Input of External Photons

7.2.2 The Inapplicability of the Eddington Limit

7.2.3 Polytropic Models

7.2.4 Properties of Thick Disks

7.4 Further Developments of the Theory

7.4.2 The Fate of Angular Momentum at Large Radii

7.5.2 Interaction between the Disk and the Magnetosphere

7.5.3 Accretion Columns

7.7 Problems

**8 Electrodynamics of Compact Objects 419**

8.1 The Gold-PaciniMechanism

8.2 The Magnetospheres Surrounding Pulsars

8.2.2 The Goldreich and Julian Magnetosphere

8.2.3 The Pulsar Equation

8.2.4 The Solution

8.2.5 The Transport of Angular Momentum

8.2.6 Discussion

8.3.2 The Black Hole Equation

8.3.3 The Transport of Energy and of Angular Momentum

8.3.4 A Qualitative Discussion

8.3.5 A Simplified Discussion of Total Energetics

8.5 Disk-Jet Coupling

8.5.2 A Special Solution

8.5.3 Discussion

8.5.4 A Model Including Inertial Effects

8.5.5 A Special Solution

8.5.6 Results

8.5.7 A Brief Summary

**Appendix**

**A Propagation of Electromagnetic Waves**

**B Orbits Around Black Holes**

B.1 Problem

**C Useful Formulae**

C.1 Vector Identities

C.2 Cylindrical Coordinates

C.3 Spherical Coordinates

**Luigi Stella, INAF, Astronomical Observatory of Rome**

“This book provides an elegant, self-contained introduction to fundamental aspects of the physics of high-energy cosmic sources. Great emphasis is placed on physical intuition. Subjects such as hydrodynamics, magnetohydrodynamics, and radiative processes are presented at the level required for applications to high-energy astrophysics. Rigorous derivations are often complemented with simple arguments that facilitate an immediate grasp of the relevant processes. The chapters dealing with nonthermal particles, accretion onto compact objects, and explosions guide the reader through the foundations of some of the most relevant recent developments in these fields. Topics that are rarely addressed in introductory monographs are also treated in this book in a very clear fashion; these include pair-dominated plasmas and the electrodynamics of neutron stars and black holes. This is an excellent book and an invaluable tool for advanced students and researchers in astrophysics.”—Luigi Stella, INAF, Astronomical Observatory of Rome

**Abraham Loeb, Director, Institute for Theory and Computation and Professor of Astronomy, Harvard University**

“Mario Vietri’s book provides an excellent pedagogical introduction to the basic elements of high-energy astrophysics. The authoritative text is well balanced to serve both beginning students and advanced researchers. The comprehensive description of hydrodynamic and radiative processes from first principles is applied to the extreme environments near compact objects or energetic shocks. This exceptional combination of basic physics and its applications, rarely found to this level of rigor in a single textbook, demonstrates how fundamental physical principles shape observable phenomena in one of the most exciting frontiers of present-day astrophysics.”

**Roger Blanford, Director, Kavli Institute for Particle Astrophysics and Cosmology at Stanford University | Roger Blandford**

“Mario Vietri has written a lucid text, for both students and established researchers, that connects exciting research at the frontiers of high-energy astrophysics to basic physical processes.”

**Peter Mészáros, Eberly Chair of Astronomy and Astrophysics, and Professor of Physics, Pennsylvania State University**

This book will be a very useful addition to the library of every working theoretical astrophysicist, and a great reference for observers, students and scientists in general who are interested in the subject of high energy astrophysics. The emphasis on physical principles and basic processes, rather than on specific phenomena and observations, ensures that the material is relevant for a wide range of astrophysics applications, and will remain so for a long time.”

**Pasquale Blasi, National Institute for Astrophysics, Arcetri Astrophysical Observatory, Florence, Italy**

“A quite remarkable book, successful in explaining a wide range of high energy astrophysical phenomena in all their technical and mathematical details and in illustrating numerous physical implications of these phenomena. At the same time, concepts are discussed with such a fascinating style that the reader gets caught up in the learning process and feels able to look at any topic in a completely new way. Mario Vietri is a renowned scientist working in the field of high energy astrophysics. He has contributed seminal papers to different fields, such as galaxy formation, general relativity, gamma ray bursts and cosmic rays. The width and depth of his knowledge and his ability to charm the reader with science are effectively reflected in this book, which may easily become a new reference point for high energy astrophysicists as well as for graduate students willing to build solid foundations.”

**Physical Sciences: **
Astronomy and Astrophysics |
Experimental and Applied Physics |
Theoretical Physics

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