In "Formation and Evolution of Galaxy Disks", ASP Conference Series, Vol. 396, Proceedings of the conference held 1-5 October, 2007 at the Centro Convegni Matteo Ricci, Rome, Italy. Edited by José G. Funes, S.J., and Enrico Maria Corsini. San Francisco: Astronomical Society of the Pacific, 2008., p.241.
astro-ph/0803.1574

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DYNAMICAL EVOLUTION OF DISK GALAXIES

J. A. Sellwood


Rutgers University, Department of Physics & Astronomy,
136 Frelinghuysen Road, Piscataway, NJ 08854-8019
sellwood@physics.rutgers.edu


Abstract. Spiral patterns are important agents of galaxy evolution. In this review, I describe how the redistribution of angular momentum by recurrent transient spiral patterns causes the random speeds of stars to rise over time, metallicity gradients to be reduced, and drives large-scale turbulence in the disk, which could be important for galactic dynamos. I also outline a possible mechanism for the recurrence of spiral instabilities and supporting evidence from solar neighborhood kinematics. Finally, I confirm that cloud scattering alone would predict the local velocity ellipsoid to be flattened, contrary to long-held expectations.


Table of Contents

INTRODUCTION

DYNAMICAL CONSEQUENCES OF SHORT-LIVED SPIRAL PATTERNS
The importance of gas
Age-velocity dispersion relation
Dispersion of stellar metallicities with age
Large-scale turbulence

MECHANISM FOR RECURRENT TRANSIENT SPIRALS

VELOCITY ELLIPSOID SHAPE
Idealized simulations
Results

REFERENCES

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