Self-interacting dark matter

In astrophysics and particle physics, self-interacting dark matter (SIDM) assumes dark matter has self-interactions, in contrast to the collisionless dark matter assumed by the Lambda-CDM model. SIDM was postulated in 2000 to resolve a number of conflicts between observations and N-body simulations (of cold collisionless dark matter only) on the galactic scale and smaller. It was also used to explain the 2015 observations of ESO 146-5 the core of the Abell 3827 galaxy cluster. However, the latter finding has since been discounted based on further observations and modelling of the cluster. In astrophysics and particle physics, self-interacting dark matter (SIDM) assumes dark matter has self-interactions, in contrast to the collisionless dark matter assumed by the Lambda-CDM model. SIDM was postulated in 2000 to resolve a number of conflicts between observations and N-body simulations (of cold collisionless dark matter only) on the galactic scale and smaller. It was also used to explain the 2015 observations of ESO 146-5 the core of the Abell 3827 galaxy cluster. However, the latter finding has since been discounted based on further observations and modelling of the cluster. If the self-interacting dark matter is in the hydrostatic equilibrium, its pressure and density follow: where Φ χ {displaystyle Phi _{chi }} and Φ b {displaystyle Phi _{b}} are gravitational potential of the dark matter and baryon respectively. The equation naturally correlates the dark matter distribution to that of the baryonic matter distribution. With this correlation, the self-interacting dark matter can explain phenomena such as the Tully-Fisher relation. Self-interacting dark matter has also been postulated as an explanation for the DAMA annual modulation signal.