Extended Data Fig. 5: Results of our rotation and translation tests.

Left: change in TS when repeating the analysis using the default baseline + Sgr dSph model, but with the Sgr dSph rotated about its centre by the indicated angle (blue points); TS values > 0 indicate an improved fit (dashed grey line), with TS = 46.1 corresponding to a 5σ -significant improvement (red dashed line). Centre: same as the left panel, but for tests with the Sgr dSph template rotated about the Milky Way centre, rather than its own centre. Right: tests for translation of the Sgr dSph template. The true position of the Sgr dSph centre is the center of the plot, and the colour in each pixel indicates the change in TS if we displace the Sgr dSph centre to the indicated position; the maximum shown, at a displacement Δb ≈ − 4^∘, has TS = 40.8, corresponding to 4.5σ significance. For comparison, white contours show the original, unshifted Sgr dSph template, and the green arrow shows the direction anti-parallel to the Sgr dSph’s proper motion, back along its past trajectory; red arrows show the projection of the green arrow in the ‘ and b directions.