# A Novel Scheme for Dark Matter Annihilation Feedback in Cosmological Simulations

## TL;DR

This paper introduces a new self-consistent method for including dark matter annihilation feedback in cosmological simulations, enabling more accurate modeling of energy injection effects on gas dynamics.

## Contribution

A novel, flexible approach for simulating dark matter annihilation feedback in cosmological models, supporting adaptive time steps and various annihilation scenarios.

## Key findings

- Method agrees well with existing approaches in realistic cases
- Supports non-local energy injection and velocity-dependent cross-sections
- Compatible with cosmological and isolated halo simulations

## Abstract

We present a new self-consistent method for incorporating dark matter annihilation feedback (DMAF) in cosmological N-body simulations. The power generated by DMAF is evaluated at each dark matter (DM) particle which allows for flexible energy injection into the surrounding gas based on the specific DM annihilation model under consideration. Adaptive, individual time steps for gas and DM particles are supported and a new time-step limiter, derived from the propagation of a Sedov--Taylor blast wave, is introduced. We compare this donor-based approach with a receiver-based approach used in recent studies and illustrate the differences by means of a toy example. Furthermore, we consider an isolated halo and a cosmological simulation and show that for these realistic cases, both methods agree well with each other. The extension of our implementation to scenarios such as non-local energy injection, velocity-dependent annihilation cross-sections, and DM decay is straightforward.