Cosmology with one galaxy: An analytic formula relating Ωm with galaxy properties
Published in arxiv, 2026
Kito Liao et al 2026 arXiv [https://arxiv.org/abs/2602.05881](https://arxiv.org/abs/2602.07651)
Paper highlights:
- Cosmology is encoded in individual galaxies: we show that the matter density parameter $\Omega_m$ can be inferred directly from intrinsic galaxy properties, without relying on traditional clustering or lensing statistics. This challenges the standard separation between galaxy formation and cosmological inference.
- A simple, interpretable analytic tracer for $\Omega_m$: using symbolic regression on CAMELS simulations (including IllustrisTNG, SIMBA, Astrid, and Swift-EAGLE), we derive a compact functional form that robustly recovers $\Omega_m$ across simulation suites with only minor recalibration.
- A physical explanation: baryonic retention encodes $\Omega_m$: The tracer admits a clear interpretation, gravitational potential depth regulates baryonic retention and enrichment efficiency, naturally imprinting $\Omega_m$ into galaxy-scale observables.
This builds a direct, interpretable bridge between small-scale galaxy physics and large-scale cosmology.
You can read the paper here.