ИСТИНА

We present the results of spectroscopic observations of 102 HII regions in seven spiral galaxies (NGC 628, NGC 783, NGC 2336, NGC 6217, NGC 6946, NGC 7331, and NGC 7678). The spectral observations were carried out at the 6-m BTA telescope of the SAO RAS with the SCORPIO focal reducer in the multi-slit mode with the dispersion of 2.1 A/pixel and spectral resolution of 10 A. We estimated the oxygen and nitrogen abundances and the electron temperatures in 80 HII regions through the recent variant of the strong-line method (NS calibration). The parameters of the radial distribution (the extrapolated central intercept value and the gradient) of the oxygen and nitrogen abundances in the discs of six galaxies (all except NGC 6217) have been determined. The abundances in NGC 783, NGC 2336, NGC 6217, and NGC 7678 are measured for the first time. The extrapolated central oxygen and nitrogen abundances in studied galaxies are in the range from 8.73 to 8.94, and from 8.21 to 8.49, respectively; radial gradients of oxygen and nitrogen abundances are in the range from -0.65 to -0.38 dex/R25, and from -1.34 to -0.90 dex/R25, respectively. The only exception is SBc galaxy NGC 7678 with flat radial distribution of oxygen and nitrogen: 12+log(O/H) = 8.61-0.15(r/R25) and 12+log(N/H) = 7.89-0.34(r/R25). All galaxies from our sample follow well the general trend in the “luminosity - central metallicity” diagram for spiral and irregular galaxies.