Gamma-ray bursts are the brightest--and, until recently, among the least understood--cosmic events in the universe. Discovered by chance during the cold war, these evanescent high-energy explosions confounded astronomers for decades. But a rapid series of startling breakthroughs beginning in 1997 revealed that the majority of gamma-ray bursts are caused by the explosions of young and massive stars in the vast star-forming cauldrons of distant galaxies. New findings also point to very different origins for some events, serving to complicate but enrich our understanding of the exotic and violent universe. What Are Gamma-Ray Bursts? is a succinct introduction to this fast-growing subject, written by an astrophysicist who is at the forefront of today's research into these incredible cosmic phenomena. Joshua Bloom gives readers a concise and accessible overview of gamma-ray bursts and the theoretical framework that physicists have developed to make sense of complex observations across the electromagnetic spectrum.
He traces the history of remarkable discoveries that led to our current understanding of gamma-ray bursts, and reveals the decisive role these phenomena could play in the grand pursuits of twenty-first century astrophysics, from studying gravity waves and unveiling the growth of stars and galaxies after the big bang to surmising the ultimate fate of the universe itself. What Are Gamma-Ray Bursts? is an essential primer to this exciting frontier of scientific inquiry, and a must-read for anyone seeking to keep pace with cutting-edge developments in physics today.
Joshua S. Bloom is associate professor of astronomy at the University of California, Berkeley.
PREFACE ix Chapter 1: Introduction 1 1.1 Serendipity during the Cold War 1 1.2 A New Field Begins 7 1.3 Precise Localizations and the Search for Counterparts 10 1.4 The March 5th Event and Soft Gamma-Ray Repeaters 12 1.5 BATSE and the Great Debate 16 1.6 The Afterglow Era Begins 23 1.7 Progenitors and Diversity 29 1.8 Gamma-Ray Bursts in a Universal Context 37 Chapter 2: Into the Belly of the Beast 40 2.1 What Are Gamma-Ray Bursts? 40 2.2 Understanding the Origin of the High-Energy Emission 52 2.3 The Central Engine 62 Chapter 3: Afterglows 72 3.1 Phenomenology 73 3.2 Origin of the Emission 90 3.3 Evidence for Jetting 105 3.4 Late-Time Observations 111 Chapter 4: The Events in Context 113 4.1 Local Scales 114 4.2 Galactic Scales 121 4.3 Universal Scales 127 Chapter 5: The Progenitors of Gamma-Ray Bursts 135 5.1 A Massive-Star Origin 137 5.2 Mergers of Compact Objects 150 5.3 Extragalactic Magnetars 163 5.4 Classification Challenges 165 Chapter 6: Gamma-Ray Bursts as Probes of the Universe 169 6.1 Studies of Gas, Dust, and Galaxies 171 6.2 The History of Star Formation 177 6.3 Cosmic Dawn: Measuring Reionization and the First Objects in the Universe 181 6.4 Neutrinos, Gravitational Waves, and Cosmic Rays 191 6.5 Quantum Gravity and the Expansion of the Universe 195 6.6 The Future of Gamma-Ray Bursts: At the Nexus of Physical and Astrophysical Inquiry 200 NOTES 203 SUGGESTIONS FOR FURTHER READING 227 GLOSSARY 231 INDEX 249