The El Gordo galaxy cluster challenges {\Lambda}CDM for any plausible collision velocity

Understand

El Gordo (ACT-CL J0102-4915) is an extraordinarily large and bright galaxy cluster collision.

• In a previous study, we found that El Gordo is in $6.2\sigma$ tension with the $\Lambda$CDM standard model when assuming the nominal mass and infall velocity values from the hydrodynamical simulations of Zhang et al.
• ($M_{200} = 3.2 \times 10^{15} M_{\odot}$ and $V_{\textrm{infall}} = 2500~\textrm{km~s}^{-1}$, respectively).
• The recent weak lensing study of Kim et al.