New Insights into Dark Matter Halo Dynamics from Resonant Self-interacting Models

Recent research has explored the dynamics of self-interacting dark matter (SIDM) models, particularly focusing on a velocity-dependent cross section that exhibits a resonant enhancement around 16 km/s. The study, titled "Gravothermal Catastrophe in Resonant Self-interacting Dark Matter Models," authored by Vinh Tran, Daniel Gilman, Mark Vogelsberger, Xuejian Shen, Stephanie O'Neil, and Xinyue Zhang, investigates how these models affect the structure of dark matter halos.

The authors conducted N-body simulations of isolated dark matter halos with a mass of approximately 10^8 solar masses. This mass was chosen to maximize the response to the resonance. The findings indicate that halos evolving under the influence of the resonant cross section deviate from the typical evolution patterns observed in halos with velocity-independent cross sections.

Key results show that halos influenced by the resonant cross section reach a lower minimum central density during core formation. Additionally, these halos take about 20% longer to return to their initial central density during the collapse phase. These deviations from expected behavior suggest that the dynamics of dark matter halos could be significantly altered in models that incorporate pronounced resonances.

The implications of this research are substantial, as they motivate further exploration of halo evolution in SIDM models. Understanding these dynamics may provide insights into the formation and behavior of dark matter in the universe, which is crucial for cosmological studies and the overall understanding of galaxy formation. The full paper can be accessed at arXiv:2405.02388.