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Colloquium Details
Date and time: Thursday, October 08, 2009 at 4:10 PM
Location: 807 Dennison
Speaker: Norman Murray from CITA
Title/topic: Stellar Feedback and Galaxy Formation
Abstract:
Star formation in galaxies is remarkably inefficient; naively one might expect that gas would cool rapidly, and collapse to form stars on a dynamical time. Observations, on the other hand, show that only two percent of the gas in a galaxy is turned into stars per dynamical time. Similar comments apply to star formation in individual giant molecular clouds. In the case of galaxies, current models attribute the low efficiency to turbulence induced by energy input from supernovae. In giant molecular clouds, the low efficiency is attributed to turbulent stirring by ionized gas (HII regions or shocked stellar winds). I will argue that the low efficiency in both cases is driven primarily by radiation pressure, from light produced by massive star clusters, on dust. I will present models that reproduce the Carina and Westerlund I clusters in the Milky Way, the 20 or so massive clusters in M82, and even more massive clusters, with masses up to 100 million solar masses, that dominate the dynamics of the ISM in ultraluminous galaxies like Arp 220. If time permits, I will discuss winds from such clusters.
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