Maps of T_e determined from [N II] (left panel) and [S III] (right panel). The elevated values in the central region for the [N II] T_e are assumed to be caused by the contribution of N⁺⁺ recombination to the [N II]5754.6 Å line; see text for a consideration. The log F(H β) surface brightness contours are as in Fig. 7. The simple means on the signal-to-error value over the two T_e maps are 52and 21, respectively.