Published in Galaxy Wars: Stellar Populations and Star Formation in Interacting Galaxies, ASP Conference Series Vol. 423, proceedings of a conference held 19-22 July 2009 at East Tennessee State University, Johnson City, Tennessee, USA. Edited by Beverly Smith, Nate Bastian, Sarah J. U. Higdon, and James L. Higdon. San Francisco: Astronomical Society of the Pacific, 2010., p.12.
astro-ph/1003.4691

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WHY ARE RING GALAXIES INTERESTING?

James L. Higdon and Sarah J. U. Higdon


Georgia Southern University, Department of Physics, Statesboro, GA 30458


Abstract: Compared with ordinary spirals, the ISM in ring galaxies experiences markedly different physical conditions and evolution. As a result, ring galaxies provide interesting perspectives on the triggering/quenching of large scale star formation and the destructive effects of massive stars on molecular cloud complexes. We use high resolution radio, sub-mm, infrared, and optical data to investigate the role of gravitational stability in star formation regulation, factors influencing the ISM's molecular fraction, and evidence of peculiar star formation laws and efficiencies in two highly evolved ring galaxies: Cartwheel and the Lindsay-Shapley ring.


Table of Contents

INTRODUCTION

STAR FORMATION RATES IN RING GALAXIES

THE INTERSTELLAR MEDIUM IN RING GALAXIES
Atomic Hydrogen
Molecular Gas in the L-S Ring Galaxy

STAR FORMATION PROCESSES IN THE RING
The Role of Gravitational Instabilities
Evidence for Peculiar Star Formation Laws
Enhanced Star Formation Efficiencies

WHY IS THE MOLECULAR GAS FRACTION SO LOW?

SUMMARY AND FUTURE PROSPECTS

REFERENCES

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