Galactic Winds 1 Galactic Winds Sylvain Veilleux Department of Astronomy, University of Maryland, College Park, MD 20742; E-mail: veilleux@astro.umd.edu Gerald Cecil Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27599-3255; E-mail: cecil@physics.unc.edu Joss Bland-Hawthorn Anglo-Australian Observatory, Epping, NSW, Australia; E-mail: jbh@aaoepp.aao.gov.au Key Words galaxies: evolution — galaxies: halos — galaxies: intergalactic medium — galaxies: kinematics and dynamics — galaxies: nuclei Abstract Galactic winds are the primary mechanism by which energy and metals are recycled in galaxies and are deposited into the intergalactic medium. New observations are revealing the ubiquity of this process, particularly at high redshift. We describe the physics behind these winds, discuss the observational evidence for them in nearby star-forming and active galaxies and in the high-redshift universe, and consider the implications of energetic winds for the formation and evolution of galaxies and the intergalactic medium. To inspire future research, we conclude with a set of observational and theoretical challenges. CONTENTS INTRODUCTION .................................... 2 Fundamental role ....................................... 2 Early History ......................................... 3 Review structure ....................................... 4 BASIC PHYSICS .................................... 4 Sources of Energy ....................................... 4 Wind-blown bubbles ...................................... 7 Galactic winds ........................................ 9 Hydrodynamical Simulations ................................. 10 MAJOR WINDBLOWN EVENTS IN THE LMC & GALAXY ........... 11 Large Magellanic Cloud ................................... 11 Nuclear Wind in the Galaxy ................................. 12