Radial dependence of 12 + log(O/H)_PP04. The red dots show the measurement at the SN position. The horizontal dashed lines indicate the metallicity measured from the total galaxy spectra (Table 4). As a guide to the eye, we plot metallicity gradients of −0.022, −0.035, −0.030, −0.058 and + 0.007 dex kpc^-1 (from top to bottom) with the solid lines. We estimate that the accuracy of these gradients is ~0.005. The blue squares show the metallicities measured from the azimuthally averaged spectra. The points shown with the cross and plus signs are the metallicities of the H ii regions discussed in Sect. 4.1.6.