Invited lecture at Evry Schatzman School 2010: Star Formation in the Local Universe.
astro-ph/1106.1793

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Abstract: This lecture reviews fundamental physical processes on star formation in galaxy interactions and mergers. Interactions and mergers often drive intense starbursts, but the link between interstellar gas physics, large scale interactions, and active star formation is complex and not fully understood yet. We show that two processes can drive starbursts: radial inflows of gas can fuel nuclear starbursts, triggered gas turbulence and fragmentation can drive more extended starbursts in massive star clusters with high fractions of dense gas. Both modes are certainly required to account for the observed properties of starbursting mergers. A particular consequence is that star formation scaling laws are not universal, but vary from quiescent disks to starbursting mergers. High-resolution hydrodynamic simulations are used to illustrate the lectures.

Table of Contents

INTRODUCTION

GALAXY-SCALED STAR FORMATION AND ISM DYNAMICS - BASIC FACTS

Disk stability and star formation

The heterogeneous and turbulent ISM

Star formation in the turbulent ISM

DYNAMICS OF GALAXY INTERACTIONS AND MERGERS

Dynamical Friction

Violent Relaxation

Gas response and tidal torques

STAR FORMATION TRIGGERING IN INTERACTIONS - FROM MERGERS TO STARBURSTS

Main observed facts

Standard theory of merger-induced starbursts: gas inflows and nuclear starbursts

Limitations of the standard theory

Star formation in mergers: effect of the turbulent, cloudy ISM

From triggered turbulence to dense gas excess and starbursts

Implications for star formation "laws"

Summary

STRUCTURE FORMATION IN MERGERS, SUPER STAR CLUSTERS AND GLOBULAR CLUSTERS

CONCLUSION AND IMPLICATIONS FOR GALAXY FORMATION

REFERENCES