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Cambridge University Press 052175576X - Measuring and Modeling the Universe Edited by Wendy L. Freedman Frontmatter More information

Measuring and Modeling the Universe

We have just concluded a remarkable century: the 1917 publication of Einstein’s general theory of relativity, Carnegie astronomer Edwin Hubble’s 1929 discovery of the expansion of the universe, evidence for the existence of dark matter, and the discovery of a mysterious dark energy, which is causing the universe to speed up its expansion. This comprehensive volume reviews the current theory and measurement of various parameters related to the evolution of the universe. Topics include inﬂation, string theory, the history of cosmology in the context of current measurements being made of the Hubble constant, the matter density, and dark energy, including observational results from the Sloan Digital Sky Survey, Keck, Magellan, cosmic microwave background experiments, Hubble Space Telescope,andChandra. With chapters by leading authorities in the ﬁeld, this book is a valuable resource for graduate students and professional research astronomers.

WENDY L. FREEDMAN is the Crawford H. Greenewalt Director at the Carnegie Observatories of the Carnegie Institution of Washington in Pasadena, California. She received a Carnegie Fellowship at the Observatories in 1984, and joined the permanent faculty in 1987. Dr. Freedman is a member of the National Academy of Sciences. She received the 2002 American Philosophical Society’s Magellanic Prize, and the 1994 Marc Aaronson Prize and Lectureship, both citing her fundamental contributions to cosmology. One of her principal research interests is aimed at measuring an accurate value for the rate at which the universe is expanding, a quantity that yields both the age and size of the universe.

This series of four books celebrates the Centennial of the Carnegie Institution of Washington, and is based on a set of four special symposia held by the Observatories in Pasadena. Each symposium explored an astronomical topic of major historical and current interest at the Observatories, and each resulting book contains a set of comprehensive, authoritative reviewarticles by leading experts in the ﬁeld.

Series Editor: Luis C. Ho. Luis Ho received his undergraduate education at Harvard University and his Ph.D. in Astronomy from the University of California at Berkeley. He is currently a Staff Astronomer at the Carnegie Observatories, where he conducts research on black holes, accretion physics in galactic nuclei, and star formation processes.

Carnegie Observatories Astrophysics Series Volume 2

MEASURING AND MODELING THE UNIVERSE

Edited by WENDY L. FREEDMAN

PUBLISHED BY THE PRESS SYNDICATE OF THE UNIVERSITY OF CAMBRIDGE The Pitt Building, Trumpington Street, Cambridge, United Kingdom

CAMBRIDGE UNIVERSITY PRESS The Edinburgh Building, Cambridge CB2 2RU, UK 40 West 20th Street, NewYork, NY 10011–4211, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia Ruiz de Alarcón 13, 28014 Madrid, Spain Dock House, The Waterfront, Cape Town 8001, South Africa http://www.cambridge.org

C The Observatories of the Carnegie Institution of Washington 2004

This book is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press.

First published 2004

Printed in the United Kingdom at the University Press, Cambridge

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Contents

Introduction page xi List of Participants xiv

1 A brief history of cosmology Malcolm S.Longair 1 1.1 Introduction 1 1.2 Observational Cosmology to 1929 2 1.3 Theoretical Cosmology to 1939 6 1.4 Astrophysical Cosmology up to 1939 10 1.5 The Cosmological Problem in 1939 11 1.6 Post-War Cosmology to 1970 12 1.7 The Helium Problem and the Microwave Background Radiation 15 1.8 Conclusions 15 References 17

2 Edwin Hubble: a biographical retrospective Gale E.Christianson 19 References 28

3 Inflation Alan H.Guth 31 3.1 Introduction 31 3.2 HowDoes Inflation Work? 31 3.3 Evidence for Inflation 36 3.4 The Inflationary Power Spectrum 39 3.5 Eternal Inflation: Mechanisms 43 3.6 Eternal Inflation: Implications 46 3.7 Does Inflation Need a Beginning? 47 3.8 Calculation of Probabilities in Eternally Inflating Universes 49 3.9 Conclusion 50 References 51

4 Update on string theory John H.Schwarz 53

vi Contents

4.1 Introduction 53 4.2 1968–1993 53 4.3 1994–Present 58 4.4 Some Remaining Problems 64 References 65

5 Dark matter theory Joseph Silk 67 5.1 Introduction 67 5.2 Global Baryon Inventory 68 5.3 Galactic Baryon Inventory 69 5.4 Outﬂows 71 5.5 Prospects for Nonbaryonic Dark Matter Detection 73 5.6 Conclusions 76 References 77

6 Status of cosmology on the occasion of the Carnegie Centennial Wendy L.Freedman and Michael S.Turner 79 6.1 Introduction 79 6.2 The Cosmological Model 81 6.3 The Big Questions 92 6.4 Astrophysical Cosmology 94 6.5 Looking Forward: A Bright Future 95 References 96 6.6 Addendum: WMAP 97

7 The extragalactic distance scale Joseph B.Jensen, John L.Tonry, and John P.Blakeslee 99 7.1 Introduction 99 7.2 The Cepheid Calibration 100 7.3 Secondary Distance Indicators and the Hubble Constant 101 7.4 Systematic Uncertainties in the Cepheid Calibration 106 7.5 Peculiar Velocities 110 7.6 Bypassing the Distance Ladder 111 7.7 Probability Distributions and Systematic Uncertainties 112 7.8 Future Prospects 113 References 114

8 The Hubble constant from gravitational lens time delays Christopher S.Kochanek and Paul L.Schechter 117 8.1 Introduction 117 8.2 Time Delay Basics 118 8.3 Understanding Time Delays: A General Theory 121 8.4 Lenses Within Clusters 123 8.5 Observing Time Delays and Time Delay Lenses 124 8.6 Results: The Hubble Constant and Dark Matter 128

Contents vii

8.7 Solving the Central Concentration Problem 133 8.8 Conclusions 134 References 136

9 Measuring the Hubble constant with the Sunyaev-Zel’dovich effect Erik D.Reese 138 9.1 Introduction 138 9.2 The Sunyaev-Zel’dovich Effect 139 9.3 Measurements of the SZE 142 9.4 The Cosmic Distance Scale from SZE/X-ray Distances 148 9.5 SZE Surveys 154 9.6 Summary 155 References 156

10 How much is there of what? Measuring the mass density of the Universe Virginia Trimble 159 10.1 Introduction 159 10.2 Methods 160 10.3 Results 162 10.4 What is it All? 165 10.5 Conclusions 166 References 166

11 Big Bang Nucleosynthesis: probing the ﬁrst 20 minutes Gary Steigman 169 11.1 Introduction 169 11.2 An Overviewof BBN 170 11.3 Primordial Abundances 177 11.4 Confrontation of Theory with Data 187 11.5 Summary and Conclusions 191 References 194

12 Cosmological results from the 2dF Galaxy Redshift Survey Matthew Colless 196 12.1 Introduction 196 12.2 The Large-scale Structure of the Galaxy Distribution 198 12.3 The Bias of the Galaxy Distribution 200 12.4 Redshift-space Distortions 201 12.5 The Mass Density of the Universe 202 12.6 Joint LSS-CMB Estimates of Cosmological Parameters 203 12.7 The Galaxy Population 204 12.8 Conclusions 205 References 206

13 Large-scale structure in the Sloan Digital Sky Survey Mariangela Bernardi 207

viii Contents

13.1 Introduction to the SDSS 207 13.2 Galaxy Clustering 208 13.3 Angular Clustering 209 13.4 Clustering in z Space 215 References 218

14 LIGO at the threshold of science operations Albert Lazzarini 219 14.1 Introduction 219 14.2 S1 Data Analysis Activities 220 14.3 Summary 232 14.4 Note added in proof 233 References 233

15 Why is the Universe accelerating? Sean M.Carroll 235 15.1 Introduction 235 15.2 The Mysteries 236 15.3 What Might be Going on? 240 15.4 Observational Issues 250 15.5 Conclusions 253 References 253

16 Cosmology and life Mario Livio 256 16.1 Introduction 256 16.2 Remarks about Carbon-based Life 257 16.3 Dark Energy and Life 258 16.4 Varying Constants of Nature? 263 16.5 Is Intelligent Life Extremely Rare? 265 References 267

17 Evidence from Type Ia supernovae for an accelerating Universe and dark energy Alexei V.Filippenko 270 17.1 Introduction 270 17.2 Homogeneity and Heterogeneity 271 17.3 Cosmological Uses: LowRedshifts 272 17.4 Cosmological Uses: High Redshifts 274 17.5 Discussion 280 References 288

18 Theoretical overview of cosmic microwave background anisotropy Edward L.Wright 291 18.1 Introduction 291 18.2 Results 293

Contents ix

18.3 Discussion 307 18.4 Conclusions 307 References 307

19 The polarization of the cosmic microwave background Matias Zaldarriaga 309 19.1 Introduction 309 19.2 Temperature Anisotropies 311 19.3 Polarization 317 19.4 The E − B Decomposition and the Imprint of Gravity Waves 322 19.5 After Recombination 323 19.6 Conclusions 326 References 327

20 The Wilkinson Microwave Anisotropy Probe Lyman A.Page 330 20.1 Introduction 330 20.2 Overviewof the Mission and Instrument 331 20.3 Basic Results 337 20.4 Summary and the Future 346 References 348

21 Interferometric observations of the cosmic microwave background radiation Anthony C.S.Readhead and Timothy J.Pearson 349 21.1 Introduction 349 21.2 The CBI, the DASI, and the VSA 350 21.3 The Sky Brightness Distribution of the CMB 354 21.4 Radio Interferometric Observations of the CMB 355 21.5 Interferometer Characteristics 355 21.6 CMB Spectra from Interferometry Observations 361 21.7 Cosmological Results 364 21.8 Conclusions 367 References 368

22 Conference summary: observational cosmology Sandra M.Faber 370 22.1 Introduction 370 22.2 Current Status and Prognostications 372 22.3 Anthropic Cosmology 374 References 376

23 Measuring and modeling the Universe: a theoretical perspective Roger D.Blandford 377 23.1 Introduction 377 23.2 The Standard Model 378

x Contents

23.3 Standard Parameters 380 23.4 Cold Dark Matter 383 23.5 Large-scale Structure 383 23.6 Galaxies 384 23.7 Inﬂation 384 23.8 Second Inﬂation 385 23.9 The String Connection 387 23.10 Anthropic Reasoning 387 23.11 The Theoretical Challenge 387 Credits 389

Introduction

The Carnegie Institution of Washington celebrated its centennial in the year 2002. Following on a suggestion of staff astronomer Luis Ho, the Carnegie staff unanimously agreed that a fitting way to celebrate the Centennial of the Observatories was to have series of symposia devoted to topics where Carnegie astronomers have been actively engaged. And cosmology, with its longstanding tradition going back to Edwin Hubble near the turn of the last century, is certainly an ideal topic with which to mark a centennial celebration. Hence, Symposium 2 of the series was devoted to “Measuring and Modeling the Universe.” This symposium was held 17–22 November, 2002, in Pasadena, California, with approximately 100 people in attendance. The meeting focused on current theory and measurement of various parameters related to the evolution of the Universe. This volume presents a set of refereed review articles, written mostly by invited review speakers. Astronomy in Pasadena, and indeed for modern cosmology, was catalyzed at the turn of the last century by George Ellery Hale. It seems fitting at the occasion of the Carnegie Cen- tennial to recall some of the history that led to the development of Mount Wilson, and the establishment of the Observatory. In 1902, Hale read in the Chicago Tribune that the steel magnate, AndrewCarnegie had donated a gift of $10,000,000, founding the Carnegie In- stitution of Washington “to encourage investigation, research, and discovery in the broadest and most liberal manner, and the application of knowledge to the improvement of mankind.” Hale secured funding from the Carnegie Institution for the construction a giant, 60-inch reflecting telescope to be erected on Mount Wilson. He was convinced that the way to make progress in optical astronomy was to build large, reflecting telescopes. Remarkably, in 1906, two years before the 60-inch had even begun its operations, Hale was already devising a means for the construction of a 100-inch reflector. This telescope came into operation in 1917. Discoveries followed rapidly. First, our Sun was displaced from the center of the Uni- verse with Harlow Shapley’s study of the globular cluster system in the Milky Way. Soon thereafter followed Edwin Hubble’s discovery of Cepheids in NGC 6822, M31, and M33, establishing the existence of galaxies other than the Milky Way. By 1929, Hubble had demonstrated the correlation of distance and recession velocity. In 1915, Albert Einstein had formulated his theory of general relativity, and recognized that a stationary universe would not survive for very long — that is, it would tend to either contract or expand. Gen- eral relativity provided a framework for understanding the unexpected motions of galaxies observed by Hubble, and led to our current picture of an expanding Universe, the backbone of modern cosmology.

xii Introduction

Hale’s journey did not end with the Mount Wilson 100-inch telescope. His undergraduate days at the Massachusetts Institute of Technology in Boston motivated him to create a similar intellectual center in Pasadena. In 1910, the Throop Polytechnic Institute was a small elementary and high school with a total student body of 31. Elected to the Board of Throop trustees in 1907, Hale ultimately convinced the chemist Arthur Noyes (an old col- lege friend and, at the time, the acting president of M.I.T.) and in 1921 the physicist Robert Millikan (soon to win a Nobel Prize for his experimental work in determining the mass of the electron) to join him in establishing the California Institute of Technology. In 1921 (preceding Hubble’s discovery of galaxies and the expansion of the Universe), Hale returned to his quest for building ever-larger telescopes. He began to rally Mount Wil- son astronomer, Francis Pease, to design a 300-inch telescope. In 1928, he successfully persuaded Wickliffe Rose of the Rockefeller Foundation to give a gift of $6,000,000 toward the construction of a 200-inch telescope. The story is often told that Rockefeller emphati- cally balked at the notion of giving money to an institution of AndrewCarnegie’s (it being like bringing coals to Newcastle), and Wickliffe insisted that the money be given to Caltech rather than the Carnegie Institution. Hale had no intention of waiting for another donor (the strong preference of then Carnegie President John C. Merriam). According to his biogra- pher, Helen Wright, Hale wrote: “The general interests of scientific research are far more important than the reputation of any single institution ... The accomplishment of the work is the main thing, the other question after all is an incidental one.” In 1926, an agreement was signed between Carnegie and Caltech. The impact of World War II slowed construction, but in 1948 the 200-inch telescope on Mount Palomar became operational. In the same year an astronomy department was founded at Caltech, and Carnegie/Mount Wilson astronomers were cross-appointed to the Caltech faculty. The two institutions continued to run Palomar jointly until about 1980, as the Hale Observatory. For about two-thirds of the 20th century, it is no exaggeration to say that the telescopes and institutions connected with Mount Wilson and Mount Palomar dominated the world of astronomy. Big telescopes made possible the cosmological discoveries of the 20th century. Most recently, Carnegie, with its partners, Harvard University, M.I.T., and the Universi- ties of Michigan and Arizona, have built two twin 6.5-meter telescopes at Las Campanas in Chile: The Baade and Clay Telescopes are another very fitting tribute to the Carnegie Centennial. In the past year, three major newinstruments have been commissioned on the Magellan telescopes, opening a newera in Carnegie astronomy. And ambitious newplans are nowunderwayfor the construction of a 20-meter telescope named the Giant Magellan Telescope. The next century is beginning in as exciting manner as the previous one, and we look forward to equally interesting new results! The topics in this volume include inflation, string theory, the history of cosmology in the context of current measurements being made of the Hubble constant, the matter density, and dark energy, including observational results from the Sloan Digital Sky Survey, Keck, Mag- ellan, cosmic microwave background experiments, Hubble Space Telescope and Chandra. Unlike most symposium proceedings, all of the papers in this volume have been refereed by experts in the field. We hope that the proceedings will serve as a valuable resource for graduate students as well as professionals in astronomy and related fields. This symposium could not have taken place without the expert assistance of a number of individuals. I would like to thank Steve Wilson, Silvia Hutchison, Becky Lynn, Scott Rubel, and Greg Ortiz for organizing the meeting and taking care of the logistics. I thank also the

Introduction xiii

many individuals who served as referees of the papers. To Luis Ho, a very special thank you. Luis conceived of the Carnegie Centennial Symposia, persuaded others of us at the Observatories to become organizers of the various symposia, gently prodded and reminded us to send out notices for the meetings at the appropriate time, served as the super-editor of all four of the volumes, and after I became Director in March, 2003, he assumed most of the workload for this volume, helping to ensure that the papers were submitted by very busy authors, and that they were edited with care. And ﬁnally, I thank all of the authors who contributed to the volume.

Wendy L.Freedman Crawford H.Greenewalt Chair Director, Carnegie Observatories February 2004

List of Participants

Agol, Eric Caltech, USA Albrecht, Andreas U. C. Davis, USA Amblard, Alexandre U. C. Berkeley, USA Annis, James Fermilab, USA Bahcall, Neta Princeton University, USA Bernardi, Mariangela Carnegie Mellon University, USA Blandford, Roger Caltech, USA Blanton, Michael NewYork University, USA Bloom, Elliott SLAC/Stanford University, USA Bond, J. Richard University of Toronto, Canada Carroll, Sean University of Chicago, USA Chapman, Scott Caltech, USA Chartas, George Penn State University, USA Chave, Robert Robert Chave Applied Physics, USA Christianson, Gale Indiana State University, USA Church, Sarah Stanford University, USA Clancy, Dominic University of Crete, Greece Colless, MatthewAustralian N. University, Australia Cooray, Asantha Caltech, USA Dekel, Avishai HebrewUniversity of Jerusalem, Israel Dressler, Alan Carnegie Observatories, USA Eisenstein, Daniel University of Arizona, USA Ellis, Richard Caltech, USA Faber, Sandra U. C. Santa Cruz, USA Farrar, Glennys NewYork University, USA Filippenko, Alex U. C. Berkeley, USA Flanagan, Eanna Cornell University, USA Freedman, Wendy Carnegie Observatories, USA Gingerich, Owen Harvard University, USA Gladders, Mike Carnegie Observatories, USA Guth, Alan MIT, USA Hamuy, Mario Carnegie Observatories, USA

List of Participants xv

Hivon, Eric Caltech, USA Ho, Luis Carnegie Observatories, USA Hoekstra, Henk CITA, Canada Holz, Daniel U. C. Santa Barbara, USA Impey, Chris University of Arizona, USA Jain, Bhuvnesh University of Pennsylvania, USA Jensen, Joseph Gemini Observatory, USA Kamionkowski, Marc Caltech, USA Katz, Neal University of Massachusetts, USA Kim, Jihn E. Seoul National University, Korea Kochanek, Christopher Harvard-Smithsonian Center for Astrophysics, USA Koo, David UCO/Lick Observatory, USA Lange, AndrewCaltech, USA Lauer, Tod NOAO, USA Lazzarini, Albert Caltech, USA Lee, Jounghun University of Tokyo, Japan Livio, Mario Space Telescope Science Institute, USA Longair, Malcolm Cambridge University, UK Maller, Ariyeh University of Massachusetts, USA Marble, Andy University of Arizona, USA McClure, Megan University of Toronto, Canada Meylan, Georges Space Telescope Science Institute, USA Mould, Jeremy NOAO, USA Nishioka, Hiroaki Hiroshima University, Japan Novikov, Igor Theoretical Astrophysics Center, Denmark Outram, Phil University of Durham, UK Page, Lyman Princeton University, USA Perlmutter, Saul U. C. Berkeley, USA Peterson, Jeff Petry, Cathy Steward Observatory, USA Phillips, Mark Carnegie Observatories, Chile Phinney, E. Sterl Caltech, USA Randall, Lisa Princeton University, USA Readhead, Anthony Caltech, USA Reese, Erik U. C. Berkeley, USA Rich, R. Michael UCLA, USA Rubin, Vera DTM, USA Rusholme, Ben Stanford University, USA Sadoulet, Bernard U. C. Berkeley, USA Scargle, Jeffrey NASA, USA Schwarz, John Caltech, USA Seljak, Uros Princeton University, USA Shectman, Stephen Carnegie Observatories, USA Silk, Joseph University of Oxford, UK Steigman, Gary Ohio State University, USA Treu, Tommaso Caltech, USA Trimble, Virginia University of Maryland, USA Turner, Edwin Princeton University, USA

xvi List of Participants

Turner, Michael University of Chicago, USA Tytler, David U. C. San Diego, USA Weiner, Ben U. C. Santa Cruz, USA Wilson, Brian University of Toronto, Canada Wright, Ned UCLA, USA Zaldarriaga, Matias NewYork University, USA