Map of HESS J1825–137 showing the location and fitted power-law index of each of the 38 boxes used in independentspectral analyses. Boxes 1–12 are labelled to match the results in Aharonian et al. (2006b), whilst boxes a–z are new to this analysis. The fitted major axis used for the extent measurements is overlaid and the position of the pulsar (located at the centre of box 9) indicated. Significance contours shown correspond to 5, 10, 30, and 50σ, respectively. LS 5039 can be identified as a high-significance point source. Five spectral boxes (I–V) covering the HESS J1826–130 region are also shown.