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R. C. Mitchell, E. Baron, D. Branch (University of Oklahoma), P. Lundqvist (Stockholm Observatory), S. I. Blinnikov (Institute of Theoretical and Experimental Physics), P. H. Hauschildt (University of Georgia), C. S. J. Pun (NASA/GSFC)
Supernovae count among the most luminous phenomena in the universe, and as such they have been long sought after to serve as cosmological distance indicators. Type Ia supernova are currently the most favored, since theoretically they are the most uniform in luminosity. Type II supernovae, on the other hand, have a much larger variance in luminosity and therefore cannot provide an accurate distance by photometry alone. The Spectral-fitting Expanding Atmosphere Method (SEAM) calculates the luminosity of a supernova by matching computer models of the object's spectra to observed spectra, a feat that requires excellent radiative-transfer and hydrodynamic models and an equally powerful and accurate code. This study will introduce the program PHOENIX, and use it to examine the SN 1987A hydrodynamic models of Sergei Blinnikov and collaborators from Day 1 to Day 103. We will show that PHOENIX can be used to assess the accuracy of hydrodynamic models of supernovae, and to simulate their spectral evolution with unparalleled detail. With PHOENIX, we will be able to determine the luminosity and distance to Type II supernovae with remarkable precision.
This work was supported in part by NSF grant AST-9731450, NASA grant NAG5-3505, and an IBM SUR grant to the University of Oklahoma. Some of the calculations presented in this poster were performed at the San Diego Supercomputer Center (SDSC), supported by the NSF, and at the National Energy Research Supercomputer Center (NERSC), supported by the U.S. DOE. We thank both these institutions for a generous allocation of computer time.