A dense dark matter core of the subhalo in the strong lensing system JVAS B1938+666
Researchers used strong gravitational lensing data from JVAS B1938+666 to reconstruct a dark matter subhalo. They found that Self-Interacting Dark Matter (SIDM) or Fuzzy/Wave Dark Matter (FDM) models fit the density profile much better than the standard Navarro-Frenk-White (NFW) model. This suggests SIDM or FDM might explain observed flat cores in dark matter substructures, addressing a known discrepancy.