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The use of analytical techniques in astrophysical problems is nearing its end. Most of the problems that can be solved analytically have been done, which leaves us with the difficult, non-linear, multi-dimensional problems that require the use of computational techniques. One of the biggest problems that makes computational approaches difficult in astrophysics is the underlying dynamic range of the physical system. This is especially true in the field of cosmology. One has to couple cosmic structure formation with metal and ionizing feedback from stars and galaxies.
In order to tackle such a large dynamic range, I use ENZO, an Adaptive Mesh Refinement (AMR) N-Body + Hydrodynamics code. ENZO allows one to adaptively change the resolution based on criteria such as density, shock discontinuities, or many other requirements. By doing so, large cosmological simulations, run on thousands of processors, are capable of covering unprecedented scales.
My research deals with identifying shock structures in these simulations. Shocks are capable of accelerating cosmic ray electrons and protons that may play a role in the hydrodynamic feedback onto the surrounding medium. By constructing synthetic observational signatures of these cosmic rays, we are then able to test our understanding of their origin and behavior. In the future, I will work towards including the back-reaction of these cosmic rays onto the the hydrodynamics within the ENZO framework.
Skillman, S. W., O'Shea, B. W., Hallman, E. J., Burns, J. O., & Norman, M. L. Cosmological Shocks in Adaptive Mesh Refinement Simulations and the Acceleration of Cosmic Rays. 2008. ApJ. 689. 1063
Skillman, S. W., O'Shea, B. W., Hallman, E. J., Burns, J. O., & Norman, M. L. Shock-Accelerated Cosmic Rays in AMR Cosmological Simulations. To appear in the Course on the "Astrophysics of Galaxy Clusters" of the International School of Physics "Enrico Fermi" (Varenna, July 2008) proceedings.
Skillman, S., O'Shea, B. W., Hallman, E. J., Burns, J. O., & Norman, M. L. Shock-Generated Cosmic Rays within 3D AMR Cosmological Simulations. 211th Meeting of the AAS. January 7-11. Poster.
Talks with no proceedings:
"Shock-Accelerated Cosmic Rays in AMR Cosmological Simulations" (Talk) Skillman, Samuel W; O'Shea, Brian W.; Hallman, Eric J.; Burns, Jack O.; Norman, Michael L., Santa Fe Cosmology Workshop 2008, June 30th, 2008.
"Shock-Accelerated Cosmic Rays in AMR Cosmological Simulations" (Talk) Skillman, Samuel W; O'Shea, Brian W.; Hallman, Eric J.; Burns, Jack O.; Norman, Michael L., The Dark Universe Group Meeting, Los Alamos National Laboratory, June 26th, 2008.
"Shock-Generated Cosmic Rays in AMR Hydro/N-body Cosmological Simulations." (Talk) Skillman, Samuel W; O'Shea, Brian W.; Hallman, Eric J.; Burns, Jack O.; Norman, Michael L., JILA Astrophysics Lunch Seminar, April 25th, 2008.
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