N-Body Simulations of Frequent Self-Interacting Dark Matter
M.Fischer(1), Brüggen(1), Schmidt-Hoberg (2), Dolag (3), Kahlhoefer (4), Ragagnin (5), Robertson (6)
(1) University Hamburg, (2) DESY, (3) USM/LMU, (4) RWTH Aachen University, (5) INAF - OATs, (6) ICC
Self-interacting dark matter (SIDM) is a promising solution to potential small-scale problems with cold dark matter. Simulations are a powerful tool to study SIDM within an astrophysical context, but it is difficult to simulate all SIDM models with high fidelity. In particular, models with differential cross-sections that favour scattering by small angles (such as light-mediator models) are challenging to model numerically. We have developed a numerical scheme that is capable of modelling this small-angle scattering faithfully within the N-body method, employing a drag force as an effective description of frequent scattering. For production use, we implemented our novel scheme into the N-body code Gadget-3. So far, we have used several test problems to demonstrate that our implementation accurately models frequent scattering. In the future, we aim to combine our scheme with the widely used Monte-Carlo approach for rare scattering, allowing us to simulate dark matter candidates such as light mediator models within an astrophysical context with unprecedented accuracy.