Dark Matter and Dark Energy Interaction Influences Cosmic Halo Dynamics

A cosmological simulation study conducted by researchers at the Shanghai Astronomical Observatory, part of the Chinese Academy of Sciences, has revealed the significant influence of dark matter and dark energy interaction on the dynamics of cosmic halos.

This groundbreaking research was published in Physical Review D on November 19. The study explores two scenarios within the interacting dark matter-dark energy model: IDE I, where dark matter decays into dark energy, and IDE II, where dark energy transforms into dark matter.

The researchers utilized a specialized N-body numerical simulation program named ME-GADGET to perform high-precision simulations of cosmic structure formation under these IDE models, comparing them to the standard cold dark matter model.

They found that in the IDE I model, dark matter halos exhibited stronger alignment with the surrounding cosmic filamentary structures, suggesting that as dark matter decays, halos become looser and more influenced by their environment.

Conversely, in the IDE II model, where dark energy converts into dark matter, the alignment weakened, indicating a more compact and resistant halo structure. Zhang Jiajun, the corresponding author of the study, stated that this analogy can be likened to physical fitness; well-exercised halos are better able to resist gravitational collapse compared to those that are not.

This research is crucial as it provides a detailed understanding of intrinsic alignment, or IA, signals in halos influenced by IDE cosmology. IA is essential for interpreting data from weak gravitational lensing observations, which are affected by the non-random alignment of galaxy shapes and their relationship with large-scale cosmic structures.

The findings lay a solid groundwork for future observational projects, particularly the China Space Station Telescope, which aims to refine IA calibration models by incorporating IDE effects. Zhang emphasized that their work will assist in extracting clearer cosmological signals from upcoming data, thus addressing challenges posed by existing cosmological models such as the Hubble Tension and S8 Tension.

This research not only enhances our understanding of cosmic structure formation but also emphasizes the need for precise calibration in future astronomical surveys to accurately constrain cosmological parameters.