Oxygen and nitrogen abundances of Hii regions in six spiral galaxies

Abstract

Spectroscopic observations of 63 Hii regions in six spiral galaxies (NGC628, NGC783, NGC2336, NGC6217, NGC7331 and NGC7678) were carried out with the 6-m telescope (BTA) of Russian Special Astrophysical Observatory with the Spectral Camera attached to the focal reducer SCORPIO in multislit mode with a dispersion of 2.1Åpixel-1 and a spectral resolution of 10Å. These observations were used to estimate the oxygen and nitrogen abundances and the electron temperatures in 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 spiral galaxies NGC628, NGC783, NGC2336, NGC7331 and NGC7678 have been determined. The abundances in NGC783, NGC2336, NGC6217 and NGC7678 are measured for the first time. Galaxies from our sample follow well the general trend in the luminosity-central metallicity diagram for spiral and irregular galaxies. © 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS.