Result of the MCMAC algorithm (Dawson 2013) applied to the Bullet cluster and its bullet (group 6 in Table 2), time since collision vs. 3D velocity at the time of the collision. Contours are 68% confidence levels. Green contours do not include any constraint on the collision angle. Red contours are obtained by considering only angles ≤29°, i.e., the 1 σ constraint derived by Wittman et al. (2018). Orange contours are obtained by considering only angles between 3° and 10°, as inferred from the classical two-body collision model.