The Role of Feedback in Astrophysics

Abstract

<p> In very high resolution galaxy simulations, the supercomputers of today offer the possibility of enough resolution to capture the bubble of a supernova, though not the originating star itself. Modeling the energy released as originating from a single SPH particle initially arranged amongst a grid of particles requires the introduction of an artificial thermal conductivity term that allows the SPH method to resolve the thermal energy discontinuity inherently present in such a scenario. Such an artificial thermal conductivity is implemented in the SPH code GASOLINE. Resolution tests show that the method is insensitive to resolution changes when determining the radius of the Sedov-Taylor blast wave, and that the numerical solution agrees with the analytic prediction R = βE^1/5ρ0^-1/5t^2/5. The peak density at the shock is lower than the actual value of four times the ambient density, though it is found to scale with resolution. The density of the interior of the shock, near the center of the supernova remnant is found to be elevated compared to the value expected from the Sedov-Taylor solution, but this too is resolution dependent, and with increased resolution the central density converges towards the expected value of zero. The fluid quantities pressure and velocity are also found to be in good agreement with the profiles predicted by the analytic solution.</p>