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Event Number 2608

  Thursday, February 23rd, 2012

Astronomy Colloquium
"Star Formation, gas loss, and the molecular gas in simulations of evolving galaxies"
Time: 3:30 pm
Place: 4421 Sterling Hall
Speaker: Charlotte Christensen, University of Arizona
Abstract: The physics of the interstellar media (ISM) affects both the location of star formation and the efficiency of supernova feedback by changing the properties of the star forming gas. In most previous galaxy formation simulations, though, the cold, molecular phase of the ISM has been neglected. In this talk, I present a method for integrating the non-equilibrium molecular hydrogen (H2) abundance throughout a simulation, including such processes as dissociation by Lyman-Werner radiation, shielding of molecular gas, and H2-based star formation. I apply this model to high-resolution cosmological simulations of galaxies ranging from 10^9 to 10^12 solar masses and compare it to simulations with different ISM models. I find that the inclusion of H2 results in galaxies with clumpier ISMs and more dispersed star formation. The increased clumpiness of the gas leads to greater efficiency of supernova at removing of low-angular momentum material from the galaxy. The result is spiral galaxies with smaller bulges and more realistic rotation curve. I discuss how the these interaction between the ISM structure, star formation, and supernova feedback result in changes to the mass distribution and compare the formation histories of galaxies of different masses.
Host: Alyson Brooks
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