Astro Seminar Series

James was born in Australia and has been in North America (primarily Canada) since 1992, when he started Graduate work in Astronomy at the University of Toronto. Working with his supervisor Dick Bond at CITA he applied gasdynamical simulations to the Lyman alpha forest problem. James was a postdoc at the University of Washington working with Craig Hogan and the "N-body Shop" group where he wrote the Gasoline code with Joachim Stadel and Tom Quinn. He then came to McMaster to work with Ralph Pudtriz and Hugh Couchman in Physics and Astronomy. In 2002 James switched from full-time research to start spending time all over campus assisting researchers to develop parallel programs for the new SHARCNET supercomputer clusters. He was still involved in cutting edge astrophysics research and in July 2003 James took up a tenure track position with the Physics and Astronomy Department at McMaster. 

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Title and Abstract for James’s talk:

Superbubbles, Galactic Winds and the limits of Supernovae on Galactic Scales

Different modes of stellar feedback play different roles within galaxies.   We study the role of supernovae, an historically popular choice, on the evolution of galaxies and their stellar content.  We argue that prior work  has modeled supernovae poorly by ignoring stellar clustering and also the key physics of conduction that governs hot gas evolution.  Clustered supernovae create superbubbles, kpc-scale feedback events that can drive strong galactic winds.  We show that superbubbles can be modeled via first principles simulations without resorting to common numerical tricks that may lead to incorrect results.   In particular, we find that entropy plays an important role in generating winds.  Galaxies with superbubble feedback strongly regulate their star formation and global baryon budget.   These simulated galaxies match disk galaxy observations very well.  However, there are limits -- supernovae cannot explain the regulation of star formation in massive galaxies.