Fifty Years of Quasars

For further volumes: http://www.springer.com/series/5664 Astrophysics and Space Science Library

EDITORIAL BOARD Chairman W. B. BURTON, National Radio Astronomy Observatory, Charlottesville, Virginia, U.S.A. ([email protected]); University of Leiden, The Netherlands ([email protected])

F. BERTOLA, University of Padua, Italy J. P. CASSINELLI, University of Wisconsin, Madison, U.S.A. C. J. CESARSKY, Commission for Atomic Energy, Saclay, France P. EHRENFREUND, Leiden University, The Netherlands O. ENGVOLD, University of Oslo, Norway A. HECK, Strasbourg Astronomical Observatory, France E. P. J. VAN DEN HEUVEL, University of Amsterdam, The Netherlands V. M. KASPI, McGill University, Montreal, Canada J. M. E. KUIJPERS, University of Nijmegen, The Netherlands H. VAN DER LAAN, University of Utrecht, The Netherlands P. G. MURDIN, Institute of Astronomy, Cambridge, UK F. PACINI, Istituto Astronomia Arcetri, Firenze, Italy V. RADHAKRISHNAN, Raman Research Institute, Bangalore, India B . V. S O M OV, Astronomical Institute, Moscow State University, Russia R. A. SUNYAEV, Space Research Institute, Moscow, Russia Mauro D’Onofrio Paola Marziani Jack W. Sulentic Editors

Fifty Years of Quasars From Early Observations and Ideas to Future Research

123 Editors Mauro D’Onofrio Paola Marziani Dipartimento di Astronomia Osservatorio Astronomico di Padova UniversitadiPadova` Istituto Nazionale di Astrofisica (INAF) Padova Padova Italy Italy

Jack W. Sulentic (IAA-CSIC) Instituto de Astrofisica de Andalucia Granada Spain

ISSN 0067-0057 ISBN 978-3-642-27563-0 ISBN 978-3-642-27564-7 (eBook) DOI 10.1007/978-3-642-27564-7 Springer Heidelberg New York Dordrecht London

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Springer is part of Springer Science+Business Media (www.springer.com) To all people who dedicated most of their lives to understanding quasars • Foreword

It’s good, on occasion, to reflect on the fact that science is fundamentally a very human endeavor. The essential principles of the scientific method, drummed into us at an early age, are that science is dispassionate, objective, and self-correcting: none of which are virtues that humans necessarily come by naturally. But this view of how science works reflects an ideal to which we aspire and not necessarily the world in which we live. Scientists are in fact passionate about their work, sometimes with the result that it’s difficult to achieve true objectivity. On the other hand, science is indeed self-correcting—but usually at a much slower pace than we’d like, and with consequential forays down wrong paths while the facts get sorted out. Unfortunately, the false steps are just an inevitable part of a long process. When we attempt to examine the present state of a vibrant scientific field, we see a mixture of things that are going to be very important in the final assembly of the puzzle, things that will turn out to be of lesser importance, and some things that will turn out to be misleading, and perhaps even wrong. At any given time, however, distinguishing among these possible outcomes is not easy. But it’s entertaining to try. The editors of this volume recognized that the fiftieth anniversary of the discovery of quasars presented an interesting opportunity to open a discussion on both the current state of an exciting field of research and how it got to where it is now. The latter is actually manageable as quasars have almost no “pre-history,” notwithstanding the birth of radio astronomy, which led to identification of the first quasars, and limited work on the bright nuclei of local spiral galaxies beginning with Seyfert twenty years earlier. Fifty years is long enough for the field to have reached some level of maturity, but short enough that many of the pioneers of quasar studies are still with us, and some of them have contributed their insights and recollections to this book. In some sense, it’s surprising how slow progress has been, given that the correct basic physics was recognized by Zel’dovich and Novikov, Salpeter, and Lynden- Bell within a few years of Schmidt’s interpretation of the redshifted spectrum of 3C 273 in 1963. But over at least the first two decades of quasar research, the question that dominated discussion was whether quasars were indeed at the cosmological distances implied by their redshifts! This problem was resolved definitively (or at

vii viii Foreword least to my personal satisfaction), first, with the identification of normal galaxies in close proximity to and at the same redshift as relatively low-redshift quasars by Stockton in 1978, and then with the detection of host galaxy starlight in the spectrum of 3C 48 by Boroson and Oke in 1982 in one of the first uses of an astronomical CCD detector. Another similar diversion was the nearly universal assumption that the UV-optical-IR continuum radiation of quasars was synchrotron radiation: that the continuum shortward of one micron is thermal emission from an accretion disk was suggested by Shields in 1978 and that the near-IR continuum is reradiation by dust was posited by Rieke the same year. But these points were not broadly appreciated until the optical work of Malkan and Sargent in 1982 and the near- IR study of Sanders, Phinney, Neugebauer, Soifer, and Mathews in 1989. It was only around 15 years ago that the supermassive black hole paradigm achieved any kind of consensus, even though Rees had convincingly argued as early as 1984 that supermassive black holes in galactic nuclei are inevitable. As recently as 1992, Blandford noted that “it remains true that, even by the lax standards of astronomy, there is no proof that black holes exist in AGN, or indeed anywhere else.1”But within only a few more years, solid detection of supermassive black holes at the center of the Milky Way, M87, and NGC 4258 shifted the paradigm once again, and the question was no longer “are quasars powered by accretion onto supermassive black holes?” but instead became “why are some supermassive black holes active (i.e., accreting matter) and others are not?” So after 50 years of efforts to understand quasars, where are we currently, how did we get here, and where do we think we are headed next? That, in essence, was what the editors of this volume asked 50 quasar researchers (one for each year, it seems). Except for a short contextual introduction and a summary chapter, the book is formatted as a series of epistolary interviews: questions from the editors are phrased as letters to each of the 50 quasar researchers, with each researcher being asked to address a restricted set of questions covering topics selected by the editors. As an active researcher in the field for 35 years, I find this to be fascinating reading: this is not a formal history, but rather it has elements of collected individual memoirs. It’s not a consensus view of the state of the field either, but rather the specific points of view of individual researchers looking at the overall field of quasar research, each from his or her own vantage point, in answer to particular questions addressed to them. For me, the most interesting aspect was hearing the opinions of fellow quasarphiles on what things they believe are important now and what are the most promising directions for future research. One of the current themes in quasar research is that quasars are not only tracers of the evolution of galaxies, but agents of galactic evolution through energetic feedback processes: will this currently popular view hold up to continued scrutiny or it is another massive diversion? Will we ever understand the dichotomy between radio-loud and radio-quiet quasars? And what

1Blandford, R.D., 1992 in Relationships Between Active Galactic Nuclei and Starburst Galaxies, ed. A.V. Filippenko, ASP Conf. Series Vol. 31, p. 455. Foreword ix surprises will come with future facilities like ALMA and, we hope, with JWST and the next generation of ground-based telescopes? This book won’t answer these questions. But it will give you some things to think about.

Columbus, OH, USA Bradley M. Peterson • Preface

On a cold day in January 2010, the three Editors of this book were sitting together during a lunch break in front of a warm cup of coffee discussing the completion of the just-published Questions of Modern Cosmology—Galileo’s Legacy. That book was intended to celebrate the International Year of Astronomy and the 400 years that had passed since Galileo’s discoveries announced in Sidereus Nuncius. Several people had expressed appreciation of the editorial approach to the book edited by Mauro D’ Onofrio and Carlo Burigana. Interviews with experts who had discussed the major topics in Cosmology and Fundamental Physics. Questions and answers offered a great freedom of possibilities and made the book accessible to a broad audience interested in scientific issues. While sipping her cup of coffee Paoladistractedlysaid:“...itwouldbenicetohaveasimilarbook for quasars ...” Probably the suggestion would have passed without consequences had not Mauro promptly shouted: “Why not? We are approaching the anniversary of the discovery of quasars!” and Jack promptly added “Of course! What a great idea!” The present book was born in this way. Fifty years have indeed passed since quasar discovery. Fifty years are an ample time lapse when even human beings are led to take a breath and make a balance of their previous existence. Where did fifty years of quasar studies lead to? We would like to gain a broad view of where we stand now elucidating what we know and especially what we do not know yet. The last half-century has seen formidable achievements during which quasars never ceased to be one of the hot topics in astrophysics. Many conferences have been hosted and many textbooks and popular books about quasars have been written since 1962. Textbooks however reflect the view of a single, or a few, authoritative researchers. Since so many important questions about quasars remain open and debated we wanted to give voice to a variety of opinions that reflect different research paths as well as different views about the nature of quasars. At the same time we wanted to create a book that is readable and accessible to students and other people with an interest in Astronomy. The book on Cosmology demonstrated that this approach was feasible. So we contacted many of the most active and/or influential researchers working on quasars and most of them immediately expressed their interest for this project. Some of

xi xii Preface them were very enthusiastic and provided us with advice that helped improve the book in the course of its development—our special thanks go to Martin Gaskell, Deborah Dultzin, Martin Elvis, Hagai Netzer, and Julian Krolik. We warmly thank all contributors and Ramon Khanna, the Editor of Springer Verlag, for having believed in this project since its inception.

Venezia Mauro D’Onofrio Jack W. Sulentic Paola Marziani Acknowledgements by Contributors and Editors

H. Arp: I would like to acknowledge the time and effort of Dr. Christopher Fulton in the writing and organization of this contribution. For most of the past decade, Chris has been a close collaborator and co-author. M. Elvis: I thank my old friends Mike Watson, Andy Lawrence, Martin Ward and Ian McHardy, for careful readings that significantly improved this paper. D. Hutsemekers:´ I thank Dominique Sluse for his careful reading of Sect. 5.4. S. Lipari: I want to thank the collaboration of the members of our Team of Study of Evolution of Galaxies and QSOs (since the results presented in this review were obtained mainly by our Team): R. Terlevich, Y. Taniguchi, S. Sanchez, W. Zheng, M. Bergmann, M. Pastoriza, H. Dottori, B. Punsly, L. Colina, D. Golombeck, M. Giavalisco, Z. Zvetanov, J. Acosta Pulido, K. Janke, Ch. Bonatto, C. Winge, T. Storchi-Bergmann D. Merlo, A. Ahumada, J. Ahumada, R. Sistero, G. Carranza, M. Paz, R. Diaz. I. Marquez-Perez: I would like to thank my collaborators, especially J. Masegosa and O. Gonzalez-Mart´ ´ın. I am also grateful to JM for her encouragement, careful reading and feedback of the manuscript, that help to improve it. Financial support is acknowledged from the Spanish grant AYA2010-15169 and Junta de Andaluc´ıa TIC114 and the Excellence Project P08-TIC-03531. J.V. Narlikar: The author thanks IUCAA for secretarial assistance. G. Richards: I’d like to thank Mike Eracleous, Sarah Gallagher, Pat Hall, Paul Hewett, Karen Leighly, Daniel Proga, and Yue Shen for their contributions to the work discussed herein. I. Shlosman: I thank my collaborators and colleagues who made research such an enjoyable endevour and at the same time so challenging. I am grateful to Copernicus Astronomical Center in Warsaw for hospitality during the time this text has been largely written up, to Marek Sikora for numerous discussions about accretion

xiii xiv Acknowledgements by Contributors and Editors processes and for support, Moshe Elitzur for commenting on the first draft, and to Frederic Chopin for making this visit possible. The Editors want to thank all contributors for having accepted the challenge posed by this book. The Editors also to want thank Ramon Khanna and the staff of Springer Verlag for their support in all phases of the work. PM would like to thank her friend Giovanni Candeo for sensible support in the last few years. Contents

Acronyms ...... xxvii Contributions by all authors Web pages ...... xxxi Contributions by all authors 1 An Introduction to 50 Years of Research on Quasars...... 1 Paola Marziani, Jack W. Sulentic, and Mauro D’Onofrio 1.1 The Roaring Sixties...... 1 1.2 An Operational Definition of Quasars? ...... 4 1.3 Outline of the Book...... 6 References ...... 9 2 Quasars in the Life of Astronomers...... 11 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Suzy Collin, Giancarlo Setti, Martin Gaskell, Joe Wampler, Martin Elvis, Iraida Pronik, Vladimir Pronik, Sergey Sergeev, Aleksander Volvach, Julian Krolik, Hagai Netzer, Alfonso Cavaliere, Paolo Padovani, Halton Arp, and Jayant Narlikar 2.1 Quasars seen from Europe ...... 13 2.2 Quasars in the Early Radio Sky ...... 18 2.3 Recollections of a US Astronomer...... 24 2.4 The Development of a New Instrument ...... 35 2.5 Seyfert Galaxies as X-Ray Sources ...... 41 2.6 AGN Astrophysics in the USSR at the Time of Quasar Discovery and Afterward ...... 45 2.7 Early Modelling Attempts...... 51 2.8 The Interpretation of Quasar Spectra ...... 53 2.9 Quasars in a Cosmological Context...... 55 2.10 The Affirmation of a Unified View ...... 59

xv xvi Contents

2.11 Challenging the Standard Paradigm ...... 61 2.12 Alternative Views and Ideas...... 73 References ...... 81 3 Quasars: The Observational Perspectives...... 91 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Greg Shields, Martin Gaskell, Todd Boroson, Ari Laor, Michael Hawkins, Vladimir Pronik, Sergey Sergeev, Deborah Dultzin, Dirk Grupe, Gordon Richards, Raffaella Morganti, Aleksander Volvach, Sebastian Zamfir, Heino Falcke, Elmar K¨ording, Martin Elvis, Tracey Jane Turner, Ajit Kembhavi, Luigi Foschini, Yuri Neshpor, and Alberto Franceschini 3.1 Optical Phenomenology of Quasars ...... 94 3.2 Techniques of Discovery ...... 101 3.3 Organizing Quasar Broad-Line Diversity ...... 106 3.3.1 More on the Importance of Eigenvector 1 ...... 112 3.4 Variability ...... 114 3.5 A Photometric Monitoring Campaign ...... 118 3.6 Micro-Variability and Its Anecdotes ...... 120 3.7 Quasar Spectral Energy Distributions ...... 124 3.8 Inferences from the Quasar UV Spectrum...... 125 3.8.1 The Baldwin Effect ...... 125 3.8.2 Quasars’ Internal Emission-Line Shifts ...... 128 3.9 Radio Properties of Quasars...... 131 3.9.1 Radio Variability and Its Implications ...... 138 3.9.2 Radio Jets...... 139 3.9.3 Radio Quiet and Radio-Loud ...... 142 3.9.4 Microquasars: Inclusion of Stellar Mass Black Holes...... 150 3.9.5 Radio Loudness and a Unified View of Black Holes...... 151 3.10 X-Rays Properties of Quasars ...... 154 3.10.1 Discovering Quasars in the X-ray Domain ...... 159 3.10.2 X-Ray Emission and Absorption Lines ...... 164 3.10.3 Blurred Reflection and Absorption...... 169 3.10.4 More on X-ray Absorption: The “Warm Absorber”...... 173 3.10.5 More on the Fe K˛ Line ...... 178 3.11 The Ray Domain ...... 184 3.12 Observations at Infrared Wavelengths ...... 190 3.12.1 Evidence of a Thick Torus ...... 190 References ...... 192 Contents xvii

4 Quasars Classes and Their Relationships ...... 217 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Deborah Dultzin, Yuri Efimov, Martin Gaskell, Marianne Vestergaard, Damien Hutsem´ekers, Alberto Franceschini, Ari Laor, Dirk Grupe, Sebastian Lipari, Bego˜na Garc´ıa Lorenzo, Evencio Mediavilla, Todd Boroson, Mike Eracleous, Isabel Marquez-Perez, Elmar K¨ording, and Heino Falcke 4.1 BL Lacs and Blazars...... 219 4.2 Unobscured and Obscured Quasars: Where are They? ...... 222 4.3 Phenomenology of Absorption Lines in Quasars ...... 223 4.3.1 The Broad Absorption Lines QSOs ...... 224 4.4 Type-2 AGNs ...... 230 4.4.1 Dust Obscuration...... 235 4.5 Narrow-Line Seyfert-1 Nuclei ...... 240 4.6 The ULIRG–QSO Connection ...... 248 4.7 Double-Peaked Emitters and the Greater AGN Population...... 255 4.8 LINERs...... 258 4.9 Quasars and Microquasars ...... 266 4.9.1 Black Hole X-Ray Binaries...... 266 4.9.2 The Fundamental Plane of Black Hole Activity ...... 267 References ...... 272 5 From Observations to Physical Parameters...... 287 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Greg Shields, Shai Kaspi, Paolo Padovani, Damien Hutsem´ekers, Ross McLure, Ari Laor, Marianne Vestergaard, Bozena Czerny, Krzysztof Hryniewicz, and Deborah Dultzin 5.1 Chemical Abundances ...... 288 5.2 Reverberation Mapping ...... 290 5.2.1 Size–Luminosity Relation ...... 291 5.2.2 Stratification and Keplerian Kinematics of the BLR ..... 292 5.3 An Alternative Method to Estimate the BLR Radius ...... 293 5.4 Microlensing ...... 295 5.5 Black Hole Mass Estimation ...... 297 5.5.1 Difficulties and Uncertainties ...... 298 5.5.2 Supermassive Black-Holes and the Host Galaxy Bulge ...... 307 5.6 The Eddington Ratio ...... 319 5.7 Narrow-Line Seyfert-1 as Extreme Radiators ...... 323 5.8 Orientation Effects on Emission Lines ...... 325 References ...... 328 xviii Contents

6 Models of Quasars ...... 337 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Julian Krolik, Martin Gaskell, Suzi Collin, Hagai Netzer, Bozena Czerny, Krzysztof Hryniewicz, Luigi Foschini, Michael Eracleous, Daniel Proga, Paolo Padovani, Serguei Komissarov, Isaac Shlosman, and Martin Elvis 6.1 The Formation of Optical–UV Emission Lines and the AGN Structure ...... 339 6.2 BLR and NLR Properties...... 349 6.3 Radiation Pressure and Irregular Line Profiles ...... 354 6.4 Line and Continuum Emission from an Accretion Disk ...... 360 6.4.1 The Accretion Disk–BLR Relationship ...... 362 6.4.2 Double-Peaked Profiles and Accretion Disk Line Emission ...... 364 6.5 Origin of the Continuum ...... 368 6.5.1 Accretion Disk Structure and Continuum Emission...... 370 6.6 QSO Outflows ...... 373 6.6.1 Three Main Driving Mechanisms ...... 374 6.6.2 The Quasar Outflows ...... 375 6.6.3 Line-Driven and Magnetic Disk Winds ...... 377 6.7 Interpretation of Radio Emission ...... 381 6.7.1 Superluminal Motions ...... 381 6.7.2 Blandford–Znajek Mechanism ...... 390 6.7.3 Where is the Jet Launched? ...... 395 6.8 Mechanisms of Black Hole Accretion ...... 397 6.8.1 Accretion Drivers: Small Scales...... 398 6.8.2 Accretion Drivers: Large Scales...... 400 6.9 Modes of Disk Accretion...... 403 6.10 Relativistic Accretion Disk Theory ...... 406 6.10.1 The Nature of Internal Stress in Disks ...... 406 6.10.2 Stress at the ISCO? ...... 408 6.11 The Obscuring Torus ...... 410 6.12 A Quasar Model ...... 414 6.12.1 Parsing the Torus, Dissecting the Donut ...... 417 References ...... 420 7 Quasars in the Cosmic Environment ...... 439 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Deborah Dultzin, Gordon Richards, Johan Knapen, Isaac Shlosman, Raffaella Morganti, Renato Falomo, Mike Hawkins, Alfonso Cavaliere, Ross McLure, Greg Shields, Hagai Netzer, Daniel Proga, Alberto Franceschini, Xiaoui Fan, and Martin Elvis 7.1 The Environment Around Quasars and AGNs ...... 441 Contents xix

7.2 The Observational Evidence of Infall from the Circumnuclear Environment ...... 448 7.3 Evidence of Feedback ...... 459 7.3.1 Interplay Between Radio Jet and the Environment ...... 459 7.3.2 Feedback Due to Quasar Winds ...... 462 7.4 Quasars from Well Dressed to Naked...... 464 7.5 Quasar Birth and Evolution ...... 471 7.6 Black Hole Growth and Extremely Large Black Holes ...... 478 7.6.1 Primordial (Seed) Black Holes ...... 478 7.6.2 Black Hole Growth Through Galaxy Evolution ...... 482 7.7 Dust-Enshrouded Quasars ...... 484 7.8 High-Redshift QSOs...... 486 7.9 The Optical Luminosity Function of QSOs and Its Evolution..... 490 7.10 QSO Large-Scale Environment and Clustering ...... 493 7.11 What Are Quasars Telling Us on Structure Formation? ...... 495 7.12 QSOs as Cosmological Probes ...... 499 References ...... 505 8 The Future of Quasar Studies ...... 521 Contributions by Mauro D’Onofrio, Paola Marziani, Jack W. Sulentic, Suzy Collin, Alberto Franceschini, Martin Elvis, Shai Kaspi, Marianne Vestergaard, Paolo Padovani, Johan Knapen, and Isaac Shlosman 8.1 The Past Achievements ...... 522 8.2 Future Observational Prospects ...... 524 8.2.1 Visual–Near IR ...... 524 8.2.2 IR–mm Domain ...... 526 8.2.3 X-Ray...... 528 8.3 Reverberation Mapping ...... 531 8.3.1 Two-Dimensional Reverberation Mapping and Structure of the BLR ...... 533 8.3.2 Dust Reverberation Mapping ...... 536 8.3.3 X-Ray FeK˛ Reverberation Mapping...... 536 8.4 Digital Observatories ...... 537 8.5 The Detection of Infalling Matter and the Accretion Scenario .... 542 References ...... 543 9 Fifty Years of Quasars: Current Impressions and Future Perspectives ...... 549 Contributions by Jack W. Sulentic, Paola Marziani, and Mauro D’Onofrio 9.1 Summary of Achievements...... 549 9.2 Areas of Major Achievements ...... 551 9.2.1 A Large Population of Quasars and Unification ...... 551 9.2.2 A Universe Filled with Quasars ...... 551 xx Contents

9.2.3 Probing Deep ...... 552 9.2.4 Self-Similarity of Accretion Processes...... 553 9.3 The Weak Points or Some Questions That Remain for the Editors and Probably Many Readers as Well...... 553 9.3.1 The Nature of Radio Jets and the RL–RQ Dichotomy ... 553 9.3.2 The Origin of Continuum Emission in Radio-Quiet Quasars ...... 554 9.3.3 The Broad-Line-Emitting Region(s) ...... 555 9.3.4 Feedback and the Joint Evolution of Quasars and Their Host Galaxies ...... 556 9.4 Areas Supported by Partial or Inconclusive Evidence ...... 557 9.4.1 The Quasar Environment ...... 557 9.4.2 The Smoking Gun of Infall ...... 557 9.4.3 Is It Really a Black Hole? ...... 558 9.4.4 The Quest for an H–R Diagram ...... 558 9.5 The Future: Peering into the First of the Next 50 Years ...... 559 9.5.1 Do We Really Need to Find More Quasars? ...... 560 9.5.2 Toward a Deeper Physical Understanding ...... 563 9.5.3 The New Redshift Frontier ...... 564 9.5.4 Moore’s Law in Quasar Astronomy ...... 566 9.5.5 Quasars, the Foundations of Cosmology and Fundamental Physics ...... 567 References ...... 567

Index ...... 571 Contributors

Halton Arp Max Planck Institut f¨ur Astrophysik, Karl Schwarschild Str. 1, Post- fach 1317, D-85741 Garching bei M¨unchen, Germany, [email protected] Author’s contribution in: Chap. 2, Sect. 2.11,p.61. Todd Boroson National Optical Astronomy Observatory, Tucson, AZ, USA, tyb@ noao.edu Author’s contribution in: Chap. 3, Sect. 3.2,p.101; Chap. 4, Sect. 4.7,p.255. Alfonso Cavaliere Dipartimento di Fisica, Universita` di Tor Vergata, via Ricerca Scientifica 1, 00133 Roma, Italy, [email protected] Author’s contribution in: Chap. 2, Sect. 2.9,p.55; Chap. 7, Sect. 7.5,p.471. Suzy Collin LUTH, Observatoire de Paris-Meudon, Section de Meudon, 92195 Meudon, France, [email protected] Author’s contribution in: Chap. 2, Sect. 2.1,p.13; Chap. 6, Sect. 6.1,p.344; Chap. 6, Sect. 6.4,p.360; Chap. 8, Sect. 8.1,p.522. Bozena Czerny Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland, [email protected] Author’s contribution in: Chap. 5, Sect. 5.6,p.321; Chap. 6, Sect. 6.4.1,p.362; Chap. 6, Sect. 6.5.1,p.371. Mauro D’Onofrio Dipartimento di Astronomia, Universita` degli Studi di Padova, Vicolo Osservatorio 3, I35122 Padova, Italy, [email protected] Co-editor of the book. Deborah Dultzin Instituto de Astronomia, Universidad Nacional Autonoma de Mexico (UNAM), Apt.do postal 70-264, Mexico, D.F., Mexico, deborah@astroscu. unam.mx Author’s contribution in: Chap. 3, Sect. 3.6,p.120; Chap. 4, Sect. 4.1,p.219; Chap. 5, Sect. 5.8,p.325; Chap. 7, Sect. 7.1,p.441.

xxi xxii Contributors

Yuri Efimov Crimean Astrophysical Observatory, 98409, Ukraine, Crimea, Nauchny, [email protected] Author’s contribution in: Chap. 4, Sect. 4.1,p.221. Martin Elvis Harward Smithsonian Center for Astrophysics, Cambridge MA02138, USA, [email protected] Author’s contribution in: Chap. 3, Sect. 3.10,p.154, 155, 158; Chap. 6, Sect. 6.12, p. 414; Chap. 7, Sect. 7.12,p.504; Chap. 8, Sect. 8.2.3,p.528. Mike Eracleous Department of Astronomy and Astrophysics and Center for Gravitational Wave Physics, The Pennsylvania State University, 525 Davey Lab., University Park, PA 16802, USA, [email protected] Author’s contribution in: Chap. 4, Sect. 4.7,p.256; Chap. 6, Sect. 6.4.2,p.364. Heino Falcke Radbound Universiteit Nijmegen, Dept. Astronomy, IMAPP, The Netherlands ASTRON, Dwingeloo, The Netherlands Max-Planck Institut f¨ur Radioastronomie, Bonn, Germany, [email protected] Author’s contribution in: Chap. 3, Sect. 3.9.3,p.147; Chap. 4, Sect. 4.9.1,p.266. Renato Falomo INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 2, I35122 Padova, Italy, [email protected] Author’s contribution in: Chap. 7, Sect. 7.4,p.464. Xiaoui Fan Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson 85721, Arizona, USA, [email protected] Author’s contribution in: Chap. 7, Sect. 7.8,p.486; Chap. 7, Sect. 7.11,p.496. Luigi Foschini Istituto Nazionale di Astrofisica (INAF) - Osservatorio Astro- nomico di Brera, Via E. Bianchi, 46 - 23807 - Merate (LC) - Italy, luigi.foschini@ brera.inaf.it Author’s contribution in: Chap. 3, Sect. 3.11,p.184; Chap. 6, Sect. 6.5.1,p.372. Alberto Franceschini Dipartimento di Astronomia, Universita` degli Studi di Padova, Vicolo Osservatorio 3, I35122 Padova, Italy, [email protected] Author’s contribution in: Chap. 3, Sect. 3.12,p.190; Chap. 4, Sect. 4.4,p.230; Chap. 7, Sect. 7.7,p.484; Chap. 8, Sect. 8.2.2,p.526. Begona˜ Garc´ıa-Lorenzo Instituto de Astrof´ısica de Canarias, E-38200 La Laguna, Tenerife, Spain, [email protected] Author’s contribution in: Chap. 4, Sect. 4.5,p. 245. Martin Gaskell Departamento de F´ısica y Astronom´ıa, Facultad de Ciencias, Universidad de Valpara´ıso, Av. Gran Bretana˜ 1111, Valpara´ıso, Chile, martin. [email protected] Author’s contribution in: Chap. 2, Sect. 2.3,p.24; Chap. 3, Sect. 3.1,p.97, Sect. 3.8.1, 125; Chap. 4, Sect. 4.2,p.223; Chap. 6, Sect. 6.1,p.341. Contributors xxiii

Dirk Grupe The Pennsylvania State University, 525 Davey Lab., University Park, PA 16082, USA, [email protected] Author’s contribution in: Chap. 3, Sect. 3.7,p.124; Sect. 3.10.1,p.159; Chap. 4, Sect. 4.5,p.240. Michael Hawkins Institute for Astronomy (IfA), University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ, UK, [email protected] Author’s contribution in: Chap. 3, Sect. 3.4,p.114; Chap. 6, Sect. 7.4,p.470; Chap. 6, Sect. 7.12,p.503. Krzysztof Hryniewicz Copernicus Astronomical Center, Bartycka 18, 00-716 Warsaw, Poland, [email protected] Author’s contribution in: Chap. 5, Sect. 5.6,p.321; Chap. 6, Sect. 6.4.1,p.362; Chap. 6, Sect. 6.5.1,p.371. Damien Hutsemekers´ F.R.S. - FNRS, Institute of Astrophysics and Geophysics, University of Liege,` Allee´ du six aoˆut 17, B5c, B-4000, Liege,` Belgium, [email protected] Author’s contribution in: Chap. 4, Sect. 4.3.1,p.224, 227; Chap. 5, Sect. 5.4,p.295. Shai Kaspi School of Physics and Astronomy and the Wise Observatory, The Raymond and Beverly Sackler Faculty of Exact Science, Tel-Aviv University, Tel- Aviv 69978, Israel, [email protected] Author’s contribution in: Chap. 5, Sect. 5.2,p.290; Sect. 5.5,p.297; Sect. 5.5.1, p. 299; Chap. 8, Sect. 8.3,p.531. Ajit Kembhavi The Inter-University Centre for Astronomy and Astrophysics, Pune, India, [email protected]: Author’s contribution in: Chap. 3, Sect. 3.10.4,p.173; Chap. 3, Sect. 3.10.4,p.179. Johan Knapen Instituto de Astrofsica´ de Canarias, E-38200 La Laguna, Tenerife, Spain Departamento de Astrof´ısica, Universidad de La Laguna, E-38205 La Laguna, tenerife, Spain, [email protected] Author’s contribution in: Chap. 7, Sect. 7.2,p.449; Chap. 8, Sect. 8.5,p.542. Seguei Komissarov School of Mathematics, University of Leeds, Leeds, L529JT, UK, [email protected] Author’s contribution in: Chap. 6, Sect. 6.7.1,p.384.

Elmar Kording¨ Radbound Universiteit Nijmegen, Dept. Astronomy, IMAPP, The Netherlands, [email protected] Author’s contribution in: Chap. 3, Sect. 3.9.3,p.147; Chap. 4, Sect. 4.9.1,p.266. Julian Krolik Dept. of Physics and Astronomy, Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218-2686, USA, [email protected] Author’s contribution in: Chap. 2, Sect. 2.7,p.51; Chap. 6, Sect. 6.1,p.339; Chap. 6, Sect. 6.5,p.368; Chap. 6, Sect. 6.10,p.406. xxiv Contributors

Ari Laor Technion - Israel Institute of Technology Physics Department, Technion City, Haifa 32000, Israel, [email protected] Author’s contribution in: Chap. 3, Sect. 3.3.1, pp. 112, 127; Chap. 4, Sect. 4.4.1, p. 237, Sect. 4.8,p.258; Chap. 5, Sect. 5.5.1,p.306. Sebastian Lipari Observatorio Astronomico´ de la Univ. Nac. de Cordoba,´ Laprida 854, X5000BGR, Cordoba,´ Argentina, and CONICET, Argentina, lipari@oac. uncor.edu Author’s contribution in: Chap. 4, Sect. 4.5,p. 245. Paola Marziani INAF, Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, IT35122 Padova, Italy, [email protected] Co-editor of the book. Ross McLure Institute for Astronomy, Royal Observatory Edinburgh, Blackford Hill, Edinburgh EH9 3HJ, UK, [email protected] Author’s contribution in: Chap. 5, Sect. 5.5.1,p.300; Chapter 5, 5.6,p.319. Evencio Mediavilla Instituto de Astrof´ısica de Canarias, E-38200 La Laguna, Tenerife, Spain, [email protected] Author’s contribution in: Chap. 4, Sect. 4.5,p. 245. Raffaella Morganti Netherlands Institute for RadioAstronomy (ASTRON), Post- bus 2, 7990 AA, Dwingeloo, The Netherlands Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, The Netherlands, [email protected] Author’s contribution in: Chap. 3, Sect. 3.9,p.132; Chap. 7, Sect. 7.3.1,p.459. Jayant V. Narlikar Inter-University Centre for Astronomy and Astrophysics Post Bag 4, Ganeshkhind, Pune 411007, India, [email protected] Author’s contribution in: Chap. 2, Sect. 2.12,p.73. Yuri Neshpor Crimean Astrophysical Observatory, 98409, Ukraine, Crimea, Nauchny, [email protected] Author’s contribution in: Chap. 3, Sect. 3.11,p.188. Hagai Netzer School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel, [email protected] Author’s contribution in: Chap. 2, Sect. 2.8,p.53; Chap. 6, Sect. 6.2,p.349. Paolo Padovani European Southern Observatory, Karl-Schwarzschiled-Str. 2, D-85748 Garching bei M¨unchen, Germany, [email protected] Author’s contribution in: Chap. 2, Sect. 2.10,p.59; Chap. 5, Sect. 5.3,p.293; Chap. 6, Sect. 6.7.1,p.381; Chap. 8, Sect. 8.4,p.537. Isabel Marquez Perez´ Instituto de Astrof´ısica de Andaluc´ıa (CSIC), Granada, Spain, [email protected] Author’s contribution in: Chap. 4, Sect. 4.8,p.259. Contributors xxv

Daniel Proga Department of Physics and Astronomy, University of Nevada, LAs Vegas 4505, South Maryland Parkway, Las Vegas, Nevada 89154-4002, USA, [email protected] Author’s contribution in: Chap. 6, Sect. 6.6,p.373. Iraida Pronik Crimean Astrophysical Observatory, 98409, Ukraine, Crimea, Nauchny, [email protected] Author’s contribution in: Chap. 2, Sect. 2.6,p.45; Chap. 2, Sect. 2.6,p.47; Valdimir Pronik Crimean Astrophysical Observatory, 98409, Ukraine, Crimea, Nauchny, [email protected] Author’s contribution in: Chap. 2, Sect. 2.6,p.45; Chap. 2, Sect. 2.6,p.46; Chap. 2, Sect. 2.6,p.47; Chap. 3, Sect. 3.5,p.118. Gordon Richards Drexel University, Department of Physics, 3141 Chestnut Street, Philadelphia, PA 19104 USA, [email protected] Author’s contribution in: Chap. 3, Sect. 3.8.2,p.128; Chap. 7, Sect. 7.2,p.448. Sergey Sergeev Crimean Astrophysical Observatory, 98409, Ukraine, Crimea, Nauchny, [email protected] Author’s contribution in: Chap. 2, Sect. 2.6,p.46. Giancarlo Setti INAF-Istituto di Radioastronomia, Via P. Gobetti, 101 40129 Bologna Italy, [email protected] Author’s contribution in: Chap. 2, Sect. 2.2,p.18. Greg Shields Department of Astronomy, University of Texas, Austin, TX 78712- 0259, USA, [email protected] Author’s contribution in: Chap. 3, Sect. 3.1,p.94, Chap. 5, Sect. 5.1,p.289, Chap. 7, Sect. 7.12,p.500. Isaac Shlosman Department of Physics and Astronomy, University of Kentucky, Lexington, KY 40506-0055, USA, [email protected] Author’s contribution in: Chap. 6, Sect. 6.8,p.397; Chap. 7, Sect. 7.2,p.455; Chap. 8, Sect. 8.5,p.543. Massimo Stiavelli Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 21218, USA, [email protected] Author’s contribution in: Chap. 7, Sect. 7.10,p.493; Chap. 8, Sect. 8.2.1,p.524. Jack W. Sulentic Instituto de Astrof´ısica de Andaluc´ıa (CSIC), Granada, Spain, [email protected] Co-editor of the book. Tracey Jane Turner UMBC, 1000 Hilltop Circle, Baltimore MD 21250, USA, [email protected] Author’s contribution in: Chap. 3, Sect. 3.10.1,p.160; Chap. 3, Sect. 3.10.5, 178. Marianne Vestergaard The Dark Cosmology Centre, The Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, 2100 Copenhagen 0, Denmark xxvi Contributors

Steward Observatory and Department of Astronomy, University of Arizona, 933 N. Cherry Avenue, Tucson 85721, Arizona, USA, [email protected] Author’s contribution in: Chap. 4, Sect. 4.3,p.223, Chap. 5, Sect. 5.5.2,p.307; Chap. 8, Sect. 8.3.1,p.533. Aleksander Vol’vach Radio Astronomy Laboratory of Crimean Astrophysical Observatory, 98688, Ukraine, Crimea, Yalta, Katsively, RT-22, volvach@crao. crimea.ua Author’s contribution in: Chap. 2, Sect. 2.6,p.51; Chap. 3, Sect. 3.9.1,p.138. E. Joseph Wampler 330 Llama Ranch Lane, Santa Cruz, California CA 95060, USA, [email protected] Author’s contribution in: Chap. 2, Sect. 2.4,p. 35. Sebastian Zamfir University of Wisconsin-Stevens Point, 1848 Maria Dr Stevens Point, WI 54481-1957, USA, szamfi[email protected] Author’s contribution in: Chap. 3, Sect. 3.9.3,p.142. Acronyms

Contributions by all authors

2MASS Two Micron Sky Survey 3CR Third Cambridge Catalogue 4DE1 Four dimensional eigenvector 1 AAO Anglo Australian Observatory AAS American Astronomical Society ACIS Advanced CCD Imaging Spectrometer ADAF Advection dominated accretion flow ADIOS Advection dominated inflow–outflow solution ADS Astrophysics Data System AGB Asymptotic giant branch AGN Active galactic nucleus ASP American Society of the Pacific BAL Broad absorption line BAT Burst Alert Telescope BE Baldwin effect BELR Broad emission line region BH Black hole BLR Broad line region BPT Baldwin, Phillips, Terlevich BQS Bright Quasar Survey CCD Charge coupled device DRn Data release n CD Core dominated CDAF Advection dominated accretion flow CMB Cosmic microwave background CrAO Crimean Astrophysical Observatory CSS Compact-steep-spectrum DQE Detective quantum efficiency EGRET Energetic Gamma-ray Experiment Telescope ELAIS European Large Area ISO survey EPIC European Photon Imaging Camera

xxvii xxviii Acronyms

EV1 Eigenvector 1 EVLA Expanded Very Large Array EW Equivalent width EXIST Energetic X-ray Imaging Survey Telescope FIR Far infrared FIRST Faint Images of the Radio Sky at Twenty-Centimeters FRI Fanaroff–Riley type I FRII Fanaroff–Riley type II FSRQ Flat Spectrum Radio Quasar FWHM Full width half maximum GPS Gigahertz-peaked-spectrum GRB Gamma ray burst HDF Hubble deep field HEG High energy grating HERG High excitation radio galaxy HETG High energy transmission grating HIL High ionization line H–R Hertzsprung–Russell HST Hubble Space Telescope IAU International Astronomical Union IUE International Ultraviolet Explorer IDS Image Dissector Scanner IDV Intra day variability INOV Intra night optical variability IPCS Image Photon Counting System IR Infra-red IGM Inter galactic medium ISCO Innermost stable circular orbit ISM Inter stellar medium IXO International X-ray Observatory LBQS Large Bright Quasar Survey LERG Low excitation radio galaxy LETG Low energy transmission grating LIL Low ionization line LINER Low ionization nuclear emission-line region LISA Laser Interferometer Space Antenna LLAGN Low luminosity active galactic nucleus LOFAR Low frequency array MACHO Massive compact halo object MAGIC Major Atmospheric Gamma-ray Imaging Cherenkov MAXIM Micro-Arcosecond X-ray Imaging Mission MBH Massive black hole MEG Medium energy grating MERLIN Multi-Element Radio-Linked Interferometer MOS Metal oxide semi-conductor NASA National Aeronautics and Space Administration NED NASA Extragalactic Database NFS National Science Foundation NGC New General Catalogue Acronyms xxix

NIR Near infra-red NLR Narrow line region NLSy1 Narrow line Seyfert-1 NRAO National Radio Astronomy Observatory OM Optical microvariability PCA Principal component analysis PG Palomar-Green Pan-STARRS Panoramic Survey Telescope & Rapid Response System PKS Parkes radio source PSF Point spread function PAH Polycyclic aromatic hydrocarbon QSG Quasi stellar galaxy QSO Quasi stellar object QSS Quasi stellar source RASS ROSAT All Sky Survey RGS Reflection grating spectrometer RIAF Radiatively inefficient accretion flow RIQ Radio intermediate quasar RL Radio loud RQ Radio quiet RLQ Radio loud quasar ROSAT Rontgensatellit¨ RQQ Radio quiet quasar RXTE Rossi X-Ray Timing Explorer SAI Sternberg Astronomical Institute SAS Small astronomy satellite SDSS Sloan Digital Sky Survey SEC Secondary electron conducting SED Spectral energy distribution SINFONI Spectrograph for INtegral Field Observations in the Near Infrared SKA Square kilometer array SMBH Super massive black hole SPIE Society of Photo-Optical Instrumentation Engineers SSI Sky Survey Instrument (Ariel V) ULIRG Ultra-luminous infra-Red galaxy UV Ultraviolet VHE Very high energy VLA Very large array VLBA Very long baseline array VLBI Very long baseline interferometry VLT Very Large Telescope VLTI Very Large Telescope Interferometer VSOP VLBI Space Observatory Program XMM X-ray multi-mirror mission, XMM-Newton XBONG X-ray bright optically normal galaxy XRB X-ray binary WFXT Wide-field X-ray telescope WWII World War II • Web pages

Contributions by all authors

2QZ 2dF QSO Redshift Survey http://www.2dfquasar.org/ ALMA Atacama Large Millimiter Array http://www.eso.org/sci/facilities/alma/ ASKAP Australian Square Kilometre Array Pathfinder http://www.atnf.csiro.au/projects/askap/ Chandra http://chandra.si.edu/ E-ELT European Extremely Large Telescope http://www.eso.org/sci/facilities/eelt/ EMU Evolutionary Map of the Universe http://www.atnf.csiro.au/people/rnorris/emu eROSITA http://www.mpe.mpg.de/heg/www/Projects/EROSITA/main.html Euclid http://sci.esa.int/euclid/ IVOA International Virtual Observatory Alliance http://ivoa.net JWST James Webb Space Telescope http://www.stsci.edu/jwst/ Gravitas http://www.mpe.mpg.de/gravitas/workshop 2010/workshop.phpx GMT Giant Magellan Telescope http://www.gmto.org/ LBQS Large Bright Quasar Survey http://heasarc.gsfc.nasa.gov/W3Browse/galaxy-catalog/lbqs.html LSST Large Synoptic Survey Telescope http://www.lsst.org NASA National Aeronautic and Space Administration http://www.nasa.gov NED NASA Extragalactic Database http://ned.ipac.caltech.edu PAN-STARRS Panoramic Survey Telescope and Rapid Response System http://pan-starrs.ifa.hawaii.edu/

xxxi xxxii Web pages

SDSS Sloan Digital Sky Survey http://www.sdss.org SKA Square Kilometer Array http://www.skatelescope.org TMT Thirty Meter Telescope http://www.tmt.org/ VO-tools Virtual Observatory tools http://www.euro-vo.org/pub/fc/software.html WISE Wide-field Infrared Survey Explorer http://wise.ssl.berkeley.edu/ WFXT Wide Field X-ray Telescope http://wfxt.pha.jhu.edu/