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Session 45 - Supernovae.
Display session, Tuesday, January 14
Metropolitan Ballroom,

[45.08] A Comparison of Boltzmann and Multigroup Flux-Limited Diffusion Neutrino Transport in Core-Collapse Supernovae

O. E. B. Messer (U. Tennessee), A. Mezzacappa (ORNL), S. W. Bruenn (Florida Atlantic U.), M. W. Guidry (U. Tennessee and ORNL)

We present a comparison of three-flavor Boltzmann neutrino transport and three-flavor multigroup flux-limited diffusion (\small MGFLD) in a postbounce core collapse supernova environment. We focus our study on quantities central to the postbounce neutrino heating mechanism for reviving the stalled shock. Stationary state three-flavor neutrino distributions are developed in thermally and hydrodynamically frozen time slices obtained from core collapse and bounce simulations that implement Lagrangian hydrodynamics and \small MGFLD neutrino transport. For both transport methods, the electron neutrino and antineutrino luminosities, \small RMS energies, and inverse flux factors, all of which enter the neutrino heating rates, are computed as a function of radius, and compared. The electron neutrino and antineutrino net heating rates are also computed as a function of radius, and compared. We find that both the electron neutrino and antineutrino inverse flux factors, which describe how forward peaked these neutrinos are in the regions between their respective neutrinospheres and the shock, differ by as much as \sim30%, which translates to an equal difference in their heating rates. Because net heating involves the difference between two large numbers (heating and cooling) in the vicinity of the gain radii, the \sim30% difference in heating rates results, for a region above the gain radii, in a net heating rate for Boltzmann transport that is \sim2-3 times greater than the \small MGFLD rate. Moreover, Boltzmann transport gives less net cooling below the gain radii. The ramifications for shock revival and neutrino-driven convection are discussed.

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