Stellar Populations E-Book

Laura Greggio

• Herausgeber: Wiley-VCH
• Kategorie: Lebensstil
• Sprache: Englisch
• Veröffentlichungsjahr: 2012

Seitenzahl: 565

Beschreibung

This only up-to-date reference on Stellar Populations and development models includes coverage of distant galaxies, chemical evolution and supernovae. Written by highly acclaimed authorities in the field, the text makes use of specific problems to reveal the "kitchen secrets".

Leseprobe

Contents

Cover

Half Title page

Title page

Copyright page

Preface

Abbreviations and Acronyms

Color Plates

Chapter 1: Firm and Less Firm Outcomes of Stellar Evolution Theory

1.1 A Brief Journey through Stellar Evolution

1.2 Strengths and Weaknesses of Stellar Evolutionary Models

1.3 The Initial Mass-Final Mass Relation

Further Reading

Chapter 2: The Fundamentals of Evolutionary Population Synthesis

2.1 The Stellar Evolution Clock

2.2 The Evolutionary Flux

2.3 The Fuel Consumption Theorem

2.4 Fuel Consumptions

2.5 Population Synthesis Using Isochrones

2.6 The Luminosity Evolution of Stellar Populations

2.7 The Specific Evolutionary Flux

2.8 The IMF Scale Factor

2.9 Total and Specific Rates of Mass Return

2.10 Mass and Mass-to-Light Ratio

2.11 IMF-Dependent and IMF-Independent Quantities

2.12 The Age-Metallicity Degeneracy

Further Reading

Chapter 3: Resolving Stellar Populations

3.1 The Stellar Populations of Pixels and Frames

3.2 Simulated Observations and Their Reduction

Acknowledgments

Further Reading

Chapter 4: Age Dating Resolved Stellar Populations

4.1 Globular Cluster Ages

4.2 The Age of the Galactic Bulge

4.3 Globular Clusters in the Magellanic Clouds

4.4 Stellar Ages of the M31 Spheroid

4.5 The Star Formation Histories of Resolved Galaxies

Further Reading

Chapter 5: The Evolutionary Synthesis of Stellar Populations

5.1 Simple Stellar Populations

5.2 Spectral Libraries

5.3 Composite Stellar Populations

5.4 Evolving Spectra

Acknowledgments

Further Reading

Chapter 6: Stellar Population Diagnostics of Galaxies

6.1 Measuring Star Formation Rates

6.2 Measuring the Stellar Mass of Galaxies

6.3 Age and Metallicity Diagnostics

6.4 Star-Forming and Quenched Galaxies through Cosmic Times

Further Reading

Chapter 7: Supernovae

7.1 Observed SN Rates

7.2 Core Collapse SNe

7.3 Thermonuclear Supernovae

7.4 The Relative Role of Core Collapse and Thermonuclear Supernovae

Acknowledgments

Further Reading

Chapter 8: The IMF from Low to High Redshift

8.1 How the IMF Affects Stellar Demography

8.2 The M/L Ratio of Elliptical Galaxies and the IMF Slope below 1

8.3 The Redshift Evolution of the M/L Ratio of Cluster Ellipticals and the IMF Slope between ~ 1 and ~ 1.4

8.4 The Metal Content of Galaxy Clusters and the IMF Slope between ~ 1 and ~ 40 , and Above

Further Reading

Chapter 9: Evolutionary Links Across Cosmic Time: an Empirical History of Galaxies

9.1 The Growth and Overgrowth of Galaxies

9.2 A Phenomenological Model of Galaxy Evolution

Acknowledgments

Further Reading

Chapter 10: The Chemical Evolution of Galaxies, Clusters, and the Whole Universe

10.1 Clusters of Galaxies

10.2 Metals from Galaxies to the ICM: Ejection versus Extraction

10.3 Clusters versus Field and the Overall Metallicity of the Universe

10.4 Clusters versus the Chemical Evolution of the Milky Way

Acknowledgments

Further Reading

Index

Laura Greggio and Alvio Renzini

Stellar Populations

Related Titles

Salaris, M., Cassisi, S.Evolution of Stars and Stellar Populations386 pages 2005 ISBN: 978-0-470-09220-0

Stahler, S.W., Palla, F.The Formation of Stars865 pages with 511 figures and 21 tables 2004 ISBN: 978-3-527-40559-6

Foukal, P.V.Solar Astrophysics480 pages with 199 figures and 13 tables 2004 ISBN: 978-3-527-40374-5

Liddle, A.An Introduction to Modern Cosmology200 pages 2003 ISBN: 978-0-470-84835-7

The Authors

Dr. Laura Greggio INAFOsservatorio Astron. di PadovaVicolo dell’Osservatorio 535122 PadovaItaly

Prof. Alvio Renzini INAFOsservatorio Astron. di PadovaVicolo dell’Osservatorio 535122 PadovaItaly

Series Editors

Massimo Stiavelli Space telecope science institute3700 San Martin drBaltimore MD 21218USA

Ed Cheng Senior PartnerConceptual Analytics, LLC8209 Woburn Abbey RoadGlenn Dale, MD 20769USA

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ISBN Print 978-3-527-40918-1

ISBN ePDF 978-3-527-63663-1ISBN oBook 978-3-527-63661-7ISBN ePub 978-3-527-63662-4ISBN Mobi 978-3-527-63664-8

Preface

Galaxies are very complex systems. They are comprised of stars, gas, something else we call dark matter, and are shaped by a large variety of physical processes. This book refrains from addressing all such complexity, and is restricted instead to just one aspect: their stellar populations. Most of the radiation we receive from galaxies is star light, and star light has been detected up to redshift ~ 8, having been emitted when the Universe was just ~ 300 million years old. As most of the information we can gather on galaxies comes from star light, the ultimate aim of this book is to show how much can be learned on galaxy formation and evolution from the study of their stellar populations. Thus, this book discusses only a partial view of galaxies, but a view that provides insights that no other approach can offer. Certainly, complementary information is needed for a full description of galaxies, including how they form and evolve. Other fundamental aspects such as galaxy structure and dynamics, interactions with other galaxies and the environment, the interstellar medium and nuclear activity are however not discussed in this book.

Besides describing how stellar populations work, this book aims to present a few aspects concerning the method. In this kind of study one sometimes encounters important, even fundamental questions which nevertheless involve complicated physics. The struggle involved with understanding the physics can make one agonize over the problems for decades without much progress. Thus, it is better to ask questions that one can answer now, or within a reasonably short amount of time, and postpone the more difficult topics to the future. The complexity of Nature tends to project itself into the tools we develop in our attempts to understand it. There are situations in which an economy of means can be more effective than a cumbersome machinery with too many bells and whistles, that inevitably becomes too laborious to maneuver. Stellar population tools can offer numerous examples in this sense.

We also attempt to keep the tools we do employ as simple as possible, and include their limits and internal workings. Tools are never perfect, and inevitably imprint their defects into the results. The use of stellar population tools developed by others and downloaded from the web is now widespread, but a push button practice should be discouraged, whereby one feeds the data into a package and bothers only about the quality of the fit. Instead, looking inside the tool is highly recommended, hence becoming familiar with the assumptions and approximations on which it is built. Indeed, many of our astrophysical measurements are dominated by systematic, as opposed to statistical errors. The accuracy of a measurement, the quality of a fit, are often quantified by a χ2, which is felt to be an objective assessment of the level of confidence of the result. Yet, the subjective eye of an experienced astronomer may often grasp the material better than the χ2 automatically delivered by the package.

For all these reasons it is always advisable to keep the use of models to a minimum, as results can only gain in robustness. This is especially true in the case of stellar population models. It is in this spirit that we have in this user guide kept to a minimum the mathematical burden for the reader, relying instead as much as possible on illustrations meant to capture the core of specific astrophysical issues.

This book is meant to illustrate the specific role played by stellar populations in our attempt to understand galaxy formation and evolution. This is an extremely active field of research, where large observational and theoretical efforts are being dedicated. Thus, the traditional approach has been one in which theorists construct simulated populations of galaxies at the various redshifts, and observers deliver data sets such as catalogs of galaxies, luminosity functions, etc. Such data are then translated into mass functions, star formation rates, ages, metallicities, etc., using stellar population tools. Simulated galaxies are finally compared to real ones, similarities are appreciated, and discrepancies are addressed to adjust theoretical models in an attempt to increase the similarities and reduce the discrepancies. In practice, at each iteration adjustments are applied to the parameters used to describe the many physical processes that cannot be modeled from first principles.

This way of proceeding has resulted in great progress over the last two decades, but a different approach is now being explored thanks to the multiwavelength observational mapping of galaxies from the local Universe to almost the re-ionization epoch. Thus, a phenomenological approach is becoming possible, in which schemes are developed that describe how the population of galaxies at one cosmic epoch maps into the population of galaxies at a later epoch. One of the chapters of this book is dedicated to illustrate this approach, and how far one can reach by using only the stellar population diagnostics of galaxies, providing for each galaxy its stellar mass, star formation rate, stellar ages and metallicities. Establishing in a fully empirical way what are the main evolutionary links across cosmic time can indeed greatly help to identify the key physical processes that drive such transformations.

This is a textbook, not a review, and to make it self-sufficient and more readable no references are given in the text except for the original papers from which figures and equations have been taken. However, at the end of each chapter references to further readings are given, mentioning classical and/or recent relevant papers on the subject. The literature on stellar populations has grown immensely, beyond the capacity of individuals to absorb it all. Therefore, the choice of references listed under further readings is certainly biased by our own familiarity with specific papers, in many of which we were directly involved. On the other hand, even if extensive, list of references rapidly become obsolete nowadays, whereas online databases are continuously updates and easily browsed.

Galaxy evolution is still a field in extremely rapid development, with results being continuously superseded by wider and more accurate studies. Thus, there are issues which are still unsettled, with conflicting results having been reported, and in some cases no general convergence has been reached. In such cases, we tend to illustrate one particular option that we now feel to be more promising, but we also list references under further readings that give alternative views, providing the full range of current options. We do not venture much beyond redshift ~ 2.5−3, as in such a domain progress is now taking a sharp upturn, with galaxies being discovered at such high redshifts that they may have contributed to the cosmic re-ionization.

The book starts with a rather unconventional summary of the results of stellar evolution theory (Chapter 1), as they provide the basis for the construction of synthetic stellar populations. Current limitations of stellar evolutionary models are highlighted, which arise from the necessity to parametrize all those physical processes that involve bulk mass motions, such as convection, mixing, mass loss, etc. Chapter 2 deals with the foundations of the theory of synthetic stellar populations, and illustrates their energetics and metabolic functions, providing basic tools that will be used in subsequent chapters. Chapters 3 and 4 deal with resolved stellar populations, first addressing some general problems encountered in photometric studies of stellar fields. Then some highlights are presented illustrating our current capacity of measuring stellar ages in objects such as Galactic globular clusters, the Galactic bulge, and nearby galaxies. Chapter 5 is dedicated to the construction and exemplification of synthetic spectra of simple as well as composite stellar populations, drawing attention to those specific aspects of synthetic spectra that may depend on less secure results of stellar evolution models. Chapter 6 illustrates how synthetic stellar populations are used to derive basic galaxy properties, such as star formation rates, stellar masses, ages and metallicities, and does so for galaxies at low as well as at high redshifts. Chapter 7 is dedicated to supernovae, distinguishing them in core collapse and thermonuclear events, describing the evolution of their rates following an episode of star formation, and estimating the supernova productivity of stellar populations and their chemical yields. In Chapter 8 the stellar initial mass function (IMF) is discussed, first showing how even apparently small IMF variations may have large effects on the demography of stellar populations, and then using galaxies at low and high redshifts and clusters of galaxies to set tight constraints on possible IMF variations in space or time. In Chapter 9 the phenomenological model of galaxy evolution is presented and discussed, and, finally, in Chapter 10 we discuss chemical evolution on the scale of galaxies, clusters of galaxies and the whole Universe.

We are especially indebted to the many colleagues and friends with whom we have collaborated through the years, and from whom we have learned much of what we know on the evolution of stars and/or galaxies. We would like to mention here Nobuo Arimoto, Ralf Bender, Thomas Brown, Enrico Cappellaro, Marcella Carollo, Andrea Cimatti, Emanuele Daddi, Mark Dickinson, Natascha Föster Schreiber, Mauro Giavalisco, Bill Harris, Icko Iben Jr., Simon Lilly, Claudia Maraston, Sergio Ortolani, Giampaolo Piotto, Marina Rejkuba, Mike Rich, Bob Rood, Allen Sweigart, Daniel Thomas, Monica Tosi, Gianni Zamorani, and Manuela Zoccali.

We especially thank Claudia Maraston for having calculated for us the spectral energy distributions of composite populations that are used to illustrate Chapter 5 of this book. We would also like to thank those authors that have allowed us to reproduce some of the figures that appear in this book, including Andrea Bellini, Thomas Brown, Michele Cappellari, Santino Cassisi, Will Clarkson, Emanuele Daddi, Simona De Grandi, Renato Dupke, Valentino Gonzalez, Henry McCracken, Claudia Maraston, Antonio Marin-Franch, Alessio Mucciarelli, Sergio Ortolani, Maurilio Pannella, Yingjie Peng, Giampaolo Piotto, Lucia Pozzetti, Marina Rejkuba, Giulia Rodighiero, Andrew Stephens, Daniel Thomas, Paolo Ventura, and Norbert Werner.

Padova, June 2011

Laura Greggio and Alvio Renzini

Abbreviations and Acronyms

ACSAdvanced Camera for SurveysAGNActive Galactic NucleiAGBAsymptotic Giant BranchAICAccretion Induced CollapseBPSBinary Population SynthesisBSBlue StragglerBSGBlue SupergiantCC SupernovaeCore Collapse SupernovaeCC ClustersCool Core ClustersCDMCold Dark MatterCECommon EnvelopeCMDColor–Magnitude DiagramCOCarbon-OxygenDDDouble DegenerateDTDDistribution of the Delay TimesE-AGBEarly Asymptotic Giant BranchE-ELTEuropean Extremely Large TelescopeELTExtremely Large TelescopeFIRFar InfraredFWHMFull Width Half MaximumGOODSThe Great Observatories Origins Deep SurveyGRBGamma Ray BurstGWRGravitational Wave RadiationHBHorizontal BranchHBBHot Bottom BurningHMXBHigh Mass X-ray BinaryHRDHertzsprung–Russel DiagramHSTHubble Space TelescopeICMIntracluster MediumIGMIntergalactic MediumISMInterstellar MediumIMFInitial Mass FunctionIMFMInitial Mas – Final MassIRInfraredLBVLuminous Blue VariableLMCLarge Magellanic CloudLMXBLow-Mass X-ray BinaryLPVLong Period VariableMICADOMulticonjugate adaptive optics Imaging Camera for Deep ObservationsMLTMixing Length TheoryMSMain SequenceNICMOSNear Infrared Camera and Multi-Object SpectrometerONeMgOxygen-Neon-MagnesiumP-AGBPost Asymptotic Giant BranchPAHPolycyclic Aromatic HydrocarbonPNPlanetary NebulaPSFPoint Spread FunctionRGBRed Giant BranchRLRoche LobeRSGRed SupergiantSDSingle DegenerateSDSSSloan Digital Sky SurveySEDSpectral Energy DistributionSFHStar Formation HistorySFRStar Formation RateSGBSubgiant BranchSMGSub-millimeter GalaxySNSupernovaSNIaSupernova of type IaSNIISupernova of type IIsSFRSpecific Star Formation RateSSPSimple Stellar PopulationSWSuper WindTEThermal EquilibriumTOTurnoffTP-AGBThermally Pulsing Asymptotic Giant BranchTRGBRed Giant Branch TipUVUltravioletWDWhite DwarfWFPC2Wide Field Planetary Camera 2WHIMWarm/Hot Intergalactic MediumWRWolf–RayetZAMSZero Age Main Sequence