Can Modified Gravity (MOG) explain the speeding Bullet (Cluster)?

Understand

We apply our scalar-tensor-vector (STVG) modified gravity theory (MOG) to calculate the infall velocities of the two clusters constituting the Bullet Cluster 1E0657-06.

• In the absence of an applicable two-body solution to the MOG field equations, we adopt an approximate acceleration formula based on the spherically symmetric, static, vacuum solution of the theory in the presence of a point source.
• We find that this formula predicts an infall velocity of the two clusters that is consistent with estimates based on hydrodynamic simulations.