Colloquia and PhD Talks Schedule Summer 2014
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Qualifying Exam/2nd Year Defense "Outflows and Chemical Enrichment from Clustered Supernovae in the First Galaxies" University of Texas at Austin Qualifying Exam Committee Meeting follows at 4 PM in RLM 15.216A |
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Qualifying Exam/2nd Year Defense "The Lyman-alpha Signature of the First Galaxies" University of Texas at Austin Qualifying Exam Committee Meeting follows at 3 PM in RLM 15.216A |
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Qualifying Exam/2nd Year Defense "Formation of Massive Star Clusters - an Application of Monte Carlo Radiation Hydrodynamics" University of Texas at Austin Qualifying Exam Committee Meeting follows at 3 PM in RLM 15.202A |
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Special Seminar "Fragmentation in Primordial Gas: Improving H2 Cooling and Self-Shielding" Primordial star formation is an important field of current research, because the properties of these first stars influence the chemical enrichment, turbulent mixing, and reionisation of the primordial gas. Therefore, they define the initial conditions for subsequent star and galaxy formation.
Molecular hydrogen (H2) is the dominant coolant in primordial gas. When the H2 lines become optically thick at high densities, we need a special numerical treatment in order to model H2 cooling accurately. In order to do so, we implement a new method for the determination of effective column densities in the SPH code Gadget2. A comparison to commonly used local, isotropic methods (Sobolev, Gnedin, analytical fits) shows that these local approaches generally underestimate the photon escape fraction, because they miss the flattening of the cloud.
I will present our new method, show how it promotes fragmentation in primordial gas and discuss improvements for the commonly used local methods. Moreover, I explain how this new method can be applied to the determination of effective column densities in order to model H2 self-shielding against photodissociation in protogalactic gas clouds more accurately. University of Heidelberg, Germany (host: Volker Bromm) |
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Special Visiting Speaker Presentation (visiting: 7-14 June 2014) "Pre-supernova Convection in Massive Stars" University of Chicago host: Crag Wheeler |
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PhD Defense Presentation "Creating and Measuring White Dwarf Photospheres in a Terrestrial Laboratory" University of Texas at Austin PhD Committee Meeting follows at 12 Noon in RLM 15.216A |
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PhD Defense Presentation "Study of Galactic Clumps with Millimeter/Submillimeter Continuum and Molecular Emission: Early Stages of Massive Star Formation" University of Texas at Austin PhD Committee Meeting follows at 4 PM in RLM 15.216A |
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PhD Defense Presentation "Simulating the Formation, Properties, and Impact of Stellar Systems in the First Galaxies" University of Texas at Austin PhD Committee Meeting follows at 12 Noon in RLM 15.216A |
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Special Presentation "The Violent Early Lives of Stars and Planets" University of Texas at Austin |
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PhD Defense Presentation "The Chemical Abundances of Stars in the Halo" University of Texas at Austin PhD Committee Meeting follows at 12 Noon in RLM 15.202A |
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PhD Defense Presentation "Radiation Hydrodynamics and Simulations of Astrophysical Phenomena" University of Texas at Austin PhD Committee Meeting follows at 4 PM in RLM 15.202A |
Visitors to the Department of Astronomy can find detailed information and maps on our Visiting Austin Page.
Please report omissions/corrections to: G. Orris at argus@astro.as.utexas.edu.
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