Overview
- University of Arizona researchers report in The Astrophysical Journal that the SMC’s lack of stellar rotation stems from a direct encounter with the Large Magellanic Cloud.
- The SMC passed through the LMC’s disk a few hundred million years ago, with tidal forces scrambling stellar orbits and dense LMC gas destroying true gas rotation.
- Apparent rotation in the SMC’s gas reflects line-of-sight motions from collision-driven stretching rather than genuine spin.
- The team matched observed masses, gas content, and geometry with bespoke simulations and introduced methods to interpret scrambled post-collision kinematics.
- The findings call into question the SMC’s use as a benchmark for early, low-metallicity galaxies, with related 2025 work tying an LMC bar tilt to the SMC’s dark-matter content as a potential probe.