ARlogo Annu. Rev. Astron. Astrophys. 2002. 40:487-537
Copyright © 2002 by Annual Reviews. All rights reserved

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THE NEW GALAXY: SIGNATURES OF ITS FORMATION

Ken Freeman 1 and Joss Bland-Hawthorn 2


1 Mount Stromlo Observatory, Australian National University, Weston Creek, ACT 2611, Australia
2 Anglo-Australian Observatory, 167 Vimiera Road, Eastwood, NSW 2122, Australia


Abstract: The formation and evolution of galaxies is one of the great outstanding problems of astrophysics. Within the broad context of hierachical structure formation, we have only a crude picture of how galaxies like our own came into existence. A detailed physical picture where individual stellar populations can be associated with (tagged to) elements of the protocloud is far beyond our current understanding. Important clues have begun to emerge from both the Galaxy (near-field cosmology) and the high redshift universe (far-field cosmology). Here we focus on the fossil evidence provided by the Galaxy. Detailed studies of the Galaxy lie at the core of understanding the complex processes involved in baryon dissipation. This is a necessary first step toward achieving a successful theory of galaxy formation.


Table of Contents

PROLOGUE
The New Galaxy
Near-Field and Far-Field Cosmology
A Working Model of Galaxy Formation
Timescales and Fossils
Goals of Near-Field Cosmology

STELLAR AGE DATING

STRUCTURE OF THE GALAXY
The Bulge
The Disk
The Stellar Halo
The Dark Halo

SIGNATURES OF GALAXY FORMATION
Zero Order Signatures - Information Preserved Since Dark Matter Virialized
Introduction
Signatures of the environment
Signatures of global quantities
Signatures of the internal distribution of specific angular momentum
Signatures of the CDM hierarchy
First Order Signatures - Information Preserved Since the Main Epoch of Baryon Dissipation
The structure of the disk
Can disks preserve fossil information?
Disk heating by accretion: the thick disk
Is there an age-metallicity relation?
Effects of environment and internal evolution
Second Order Signatures - Major Processes Involved in Subsequent Evolution
Introduction
Star formation history
Low surface brightness structures in galaxies
Open clusters
Globular clusters
Structures in phase space

THE GAIASPHERE AND THE LIMITS OF KNOWLEDGE
Introduction
Chemical Signatures
Reconstructing Ancient Star Groups
Chemical Abundance Space
Chemical Trajectories
Candidates for Chemical Tagging
Summary

EPILOGUE: CHALLENGES FOR THE FUTURE

LITERATURE CITED

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