Top panel: circular brightness distribution of the simulated source (red) and the background-subtracted pulsar (black). Within 2″, where the contribution of the main nebula is negligible, the two distributions are in agreement. Bottom panel: linear brightness distribution of the main nebula along its main axis (black) within 1′ of the pulsar. We also show the predicted background (blue line). We excluded a circular region of 2″ radius around the pulsar, where point-like emission dominates.