Comparison of our original and our follow-up data in L band. The top row shows Stokes Q/I (blue) and Stokes U/I (red) of our earlier data (empty circles) and our new data (filled circles) as a function of λ² for image A (left) and image B (right). We also plot the QU fitting model (dashed lines) derived from the full frequency range of the earlier data. The bottom row shows the residual between the two datasets (q_old − q_new, u_old − u_new).