An Introduction to Distance Measurement in Astronomy E-Book

Richard de Grijs

• Herausgeber: John Wiley & Sons
• Kategorie: Lebensstil
• Sprache: Englisch

Seitenzahl: 760

Veröffentlichungsjahr: 2011

Beschreibung

Distance determination is an essential technique in astronomy, and is briefly covered in most textbooks on astrophysics and cosmology. It is rarely covered as a coherent topic in its own right. When it is discussed the approach is frequently very dry, splitting the teaching into, for example, stars, galaxies and cosmologies, and as a consequence, books lack depth and are rarely comprehensive.

Adopting a unique and engaging approach to the subject An Introduction to distance Measurement in Astronomy will take the reader on a journey from the solar neighbourhood to the edge of the Universe, discussing the range of distance measurements methods on the way.  The book will focus on the physical processes discussing properties that underlie each method, rather than just presenting a collection of techniques.

As well as providing the most compressive account of distance measurements to date, the book will use the common theme of distance measurement to impart basic concepts relevant to a wide variety of areas in astronomy/astrophysics.

The book will provide an updated account of the progress made in a large number of subfields in astrophysics, leading to improved distance estimates particularly focusing on the underlying physics.  Additionally it will illustrate the pitfalls in these areas and discuss the impact of the remaining uncertainties in the complete understanding of the Universes at large. As a result the book will not only provide a comprehensive study of distance measurement, but also include many recent advances in astrophysics.

Leseprobe

Contents

Cover

Title Page

Copyright

Dedication

Preface

Chapter 1: The Importance of Astrophysical Distance Measurements

1.1 The Distance to the Galactic Centre

1.2 The Distance to the Large Magellanic Cloud

1.3 Benchmarks Beyond the Magellanic Clouds: the 3D Universe on Large(r) Scales

Bibliography

Chapter 2: The Solar Neighbourhood

2.1 Geometric Parallax Measurements

2.2 Dynamical Parallax

2.3 Spectroscopic and Photometric Parallaxes

Bibliography

Chapter 3: From the MilkyWay to the Local Group

3.1 Basic Stellar Physics as the Key to Understanding Distance Measurements to Local Group Galaxies

3.2 Open and Globular Cluster Hertzsprung–Russell Diagrams

3.3 Giants and Supergiants as Standard Candles

3.4 White Dwarf Sequences

3.5 Period–Density Relations

3.6 Novae as Standard Candles

3.7 Geometric Methods

3.8 Pulsars: Distance Measurements Outside the ‘Classical’ Wavelength Range

Bibliography

Chapter 4: Reaching Virgo Cluster Distances and Beyond

4.1 The Hubble Space Telescope Key Project

4.2 Surface Brightness Fluctuations

4.3 The Globular Cluster Luminosity Function

4.4 The Planetary Nebulae Luminosity Function

4.5 The Tully–Fisher Relation

4.6 Distance Indicators Specific to Elliptical Galaxies

4.7 The Colour–Magnitude Relation

4.8 HII Regions as Distance Indicators?

Bibliography

Chapter 5: From Nearby Galaxy Clusters to Cosmological Distances

5.1 Cosmological Redshifts

5.2 Supernovae as Beacons

5.3 Indirect Techniques to Measure H0

Bibliography

Chapter 6: Systematic Uncertainties and Common Pitfalls

6.1 Common Biases

6.2 High Versus Low Values of the Hubble Constant: Science or Philosophy?

Bibliography

Chapter 7: Promises and Prospects

7.1 The Way Forward: Where Are Significant Gains Achievable?

7.2 The Pleiades Distance Controversy

7.3 X-Ray Scattering Haloes

7.4 Standard Sirens: Listening to Gravitational Waves

7.5 Three-Dimensional Mapping of Redshifted Neutral Hydrogen

7.6 The Present-Day Distance Ladder

Bibliography

Glossary

Figure Credits

Index

This edition first published 2011

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Library of Congress Cataloging-in-Publication Data

De Grijs, Richard, 1969-

An introduction to distance measurement in astronomy / Richard de Grijs.

p. cm.

Includes bibliographical references and index.

1. Cosmological distances–Measurement. 2. Astronomy–Methodology. I. Title.

QB991.C66D34 2011

522.87–dc23

2011014927

ISBN 978-0-470-51179-4 (cloth) – ISBN 978-0-470-51180-0 (paper) – ISBN

978-1-119-97818-3 (ePDF) – ISBN 978-1-119-97817-6 (ebook) – ISBN

978-1-119-97980-7 (ePub) – ISBN 978-1-119-97981-4 (eMobi)

To (Jie)

for her unconditional love and support throughout the years

Preface

Knowing the distance of an astrophysical object is key to understanding it: without an accurate distance, we do not know how bright it is, how large it is, or even (for great distances) when it existed. But astronomical distance measurements are difficult. Distances to stars were first measured in 1838 by Bessel, Struve and Henderson, and accurate distances to other galaxies -- even the nearest -- date only from the 1950s. This is not really surprising, since the only information we have about any object beyond our solar system is its position (perhaps as a function of time), its brightness (as a function of wavelength and time) and perhaps its radial velocity or chemical composition. Yet, from this unpromising starting point, modern astronomers have developed methods of measuring distances which can take us from the nearest star to the most distant galaxy, using techniques that vary from the mundane (the astronomical equivalent of the surveyor's theodolite) to the exotic (the bending of light in general relativity, wiggles in the spectrum of the cosmic microwave background). Nevertheless, the most accurate optical and near-infrared (near-IR) methods of distance determination, from the solar neighbourhood to the highest redshifts, in use today rely heavily on having access to accurate spectroscopy, supplemented by astrometric measurements in the Milky Way and slightly beyond.

In 1997, the Hipparcos space mission provided (for the first time) a significant number of absolute trigonometric parallaxes at milli-arcsecond-level precision across the whole sky, which had a major impact on all fields of astrophysics. In addition, during the past 10 years, the use of ground-based 8--10 m-class optical and near-IR telescopes (including the Keck Observatory, the Very Large Telescope, the twin Gemini telescopes and the Japanese Subaru telescope) and space observatories (such as the Hubble Space, Telescope, the Spitzer Space, Telescope, the Chandra X-ray Observatory and the European XMM--Newton satellite) have provided an unprecedented wealth of accurate photometric and spectroscopic data for stars and galaxies in the local Universe. Radio observations, particularly with the Very Large Baseline Array and the Japanese VERA (VLBI Exploration of Radio Astrometry, where VLBI stands for Very Long Baseline Interferometry) array, have achieved 10 micro-arsecond astrometric accuracy. Moreover, stellar models and numerical simulations are providing accurate predictions of a broad range of physical phenomena, which can now -- in principle -- be tested using accurate spectroscopic and astrometric observations (including measurements of e.g. spectral line ratios and shapes, spectral slopes, radial velocities and velocity dispersions). However, at present, comparisons of theory and observations are mainly hampered by precision (or lack thereof) in distance\break measurements/estimates.

This is a very exciting time for numerous fields relying on astronomical distance determinations. VLBI sensitivity is being expanded, allowing (for example) direct measurement of distances throughout the Milky Way and even to Local Group galaxies. The field will likely make a major push forward into the era of Gaia, optical interferometer and Extremely Large Telescope-driven science, which (for example) will allow us to determine Coma, cluster, distances without having to rely on secondary distance indicators, thus finally making the leap to accurate distance measurements well beyond the Local Group of galaxies.

In this book, we combine various aspects of distance determinations and, most importantly, the underlying physics enabling this (without being restrictive in areas where statistical and observational approaches are more relevant), from the solar neighbourhood to the edge of the Universe, exploring on the way the various methods employed to define the milestones along the road. We will emphasize recent advances made to further our physical insights. We aim to provide a snapshot of the field of distance measurement, offering not only up-to-date results and a cutting-edge account of recent progress but also full discussion of the pitfalls encountered and the uncertainties which remain. We aim to provide a roadmap for future efforts in this field, both theoretically and observationally. This book is aimed at senior undergraduate and postgraduate students, as well as researchers in the various fields touched upon by the plethora of techniques covered here. For that reason, we have tried to both explain basic physical concepts which may not necessarily be intuitively obvious and provide extensive referencing to the primary literature for follow-up reading and research.

Although our focus is on techniques of distance determination, this is intimately linked to many other aspects of astrophysics and cosmology. On our journey from the solar neighbourhood to the edge of the Universe, we shall encounter stars of all types, alone, in pairs and in clusters, their life cycles, and their explosive ends: binary stars, in particular, play an important role both in this context, e.g. in pinning down accurate distances to the Pleiades open cluster and Local Group galaxies, and in future ground- and space-based surveys (including Gaia, RAVE: the Radial Velocity Experiment, and others); the stellar content, dynamics and evolution of galaxies and groups of galaxies; the gravitational bending of starlight; and the expansion, geometry and history of the Universe. As a result, this book offers not only a comprehensive study of distance measurement but also a tour of many recent and exciting advances in astrophysics.

It has taken significant time and effort to collect and shape the contents of this book. Along the way, numerous people generously assisted or gave their time, answering my questions, providing me with feedback on earlier drafts of (parts of) chapters, keeping my imagination in check, and helping me put my thoughts (and the book's outline) in order. I would specifically like to express my gratitude to (in alphabetical order) Giuseppe Bono, Susan Cartwright, (Zuhui Fan), Stefan Gillessen, Stephen Justham, Michael Merrifield, Brent Miszalski, Göran Östlin, Mike Reid, Stephen Smartt, Nial Tanvir, Max Tegmark, Floor van Leeuwen and (Renxin Xu), as well as to my publishing contacts at Wiley, particularly Andy Slade, Jenny Cossham, John Peacock, Sarah Tilley and Janine Maer, for believing despite all odds that this project would eventually materialize. Finally, I acknowledge partial funding from the National Natural Science Foundation of China through grants 11043006 and 11073001.

Richard de Grijs Beijing February 2011