DES Y1 results: Splitting growth and geometry to test $\Lambda$CDM

Understand

We analyze Dark Energy Survey (DES) data to constrain a cosmological model where a subset of parameters -- focusing on $\Omega_m$ -- are split into versions associated with structure growth (e.g.

• $\Omega_m^{\rm grow}$) and expansion history (e.g.
• $\Omega_m^{\rm geo}$).
• Once the parameters have been specified for the $\Lambda$CDM cosmological model, which includes general relativity as a theory of gravity, it uniquely predicts the evolution of both geometry (distances) and the growth of structure over cosmic time.