ABSTRACT

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The objective of this research is to constrain star formation models with high dynamic range simulations. Current star formation simulations are based on unphysical initial conditions or artificial driving forces that mimic the energy injection from a large-scale turbulent cascade. In this project, Dr. Paolo Padoan (University of California - San Diego) will overcome this limitation by developing star formation simulations that resolve the collapse of individual protostellar cores, while including the large-scale physical processes that drive the turbulence and control the life cycle of star-forming clouds. The project will include the large-scale physics by embedding the star-formation simulations, reaching a resolution of 200 astronomical units in collapsing cores, in a 1 × 1 × 20 Kiloparsec region perpendicular to the Galactic disk. The interstellar medium in this region will be modeled using three-dimensional, compressible, ideal magneto-hydrodynamic (MHD) simulations, including density stratification in the Galactic gravitational field, gas self-gravity, radiative cooling, photoelectric and cosmic-ray heating, large-scale Galactic shear, star formation, and thermal and mechanical feedback from Type Ia, Ib+c, and Type II supernova explosions. The large samples of star-forming clouds generated by these simulations will be processed with radiative transfer codes to produce datasets of simulated dust-continuum and line emission observations.

Star formation is central to much of astrophysics and cosmology. Results from this project will be relevant to studies of the formation and evolution of galaxies and to the star formation history of the universe. They will be used to formulate sub-grid models for cosmological simulations of galaxy formation, where stellar feedback is important. The radiative transfer calculations will result in large datasets of simulated observations of star-forming clouds that will be helpful in the interpretation of real observations. Because this project will generate some of the largest simulations of supersonic turbulence to date, it will also allow high resolution studies of the statistical properties of supernova-driven MHD turbulence. Dr. Padoan, in collaboration with the San Diego Supercomputer Center, has recently started the Computational Astrophysics Data Analysis Center (CADAC), a new service to collect, share, and analyze datasets from numerical simulations. CADAC provides powerful data-storage and data-analysis resources to the astrophysical community, encouraging the early publication of numerical datasets and data-analysis tools. Through CADAC, data from this project and computational resources will be available to the scientific community, including graduate students.

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