Modeling Galaxies in the Modern Era: A Synergy between Theory and Observations

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Charting the formation and growth of galaxies, such as our own Milky Way, is a fundamental goal of modern astrophysics. The investigator studies galaxies forming their stars and changes in the appearance of galaxies with time. The investigator will study how the elements seen in galaxies change as stars form, then later explode. Answering these questions requires a technique called Spectral Energy Distribution (SED) fitting, where astronomers model the light coming from a galaxy, then infer its physical properties. However, associated with the fitting technique are potential errors that could result in a misunderstanding of the physical properties of galaxies. The investigator will model potential errors and therefore derive a more accurate view of galaxies in the distant Universe. The investigators will improve on their theoretical models for galaxies by running large-scale computer simulations of galaxies forming and changing. These simulations use many millions of computer hours. They will model galaxy changes with time, starting from soon after the Big Bang until present times.The investigator will also work with high school teachers visiting in the campus in the summer to train them in the software and background material that will accompany the lesson plans. The lesson modules will leverage the capabilities of both the World-Wide Telescope and the Galaxy Zoo projects. The investigator will transform the cosmological simulations into fly-through interactive movies to show the public the beauty of these fascinating simulations.The investigator's goal for this project is testing SED fitting techniques. They will employ a series of cosmological galaxy formation simulations in which individual galaxies change with from early Universe to the present time. They will select the galaxies to zoom in on from state-of-the-art cosmological hydrodynamic simulations and run models ranging from Milky Way mass through the progenitors of the most massive clusters at present epoch. The investigators will next use their detailed simulations and compute what the astronomers would see, given the telescope characteristics. Because astronomers use programs to deduce the physical properties from observations, the investigator can compare the galaxy simulation with the values deduced from the simulated observations. This will test the accuracy of observational results, and the comparison will be used to devise better ways of making astronomical measurements. Their main goals are to improve models of star formation rate, stellar mass, and metallicity estimates.