Oxygen and nitrogen abundances of HII regions in six spiral galaxies

TL;DR

This study measures oxygen and nitrogen abundances in HII regions across six spiral galaxies using spectroscopic data, revealing radial distribution patterns and first-time measurements for some galaxies, contributing to understanding galaxy chemical composition.

Contribution

It provides new measurements of elemental abundances in several spiral galaxies and analyzes their radial distribution, expanding the data on galaxy metallicity profiles.

Findings

Abundances in four galaxies are measured for the first time.

Galaxies follow the general luminosity-metallicity trend.

Radial abundance gradients are characterized for multiple galaxies.

Abstract

Spectroscopic observations of 63 HII regions in six spiral galaxies (NGC 628, NGC 783, NGC 2336, NGC 6217, NGC 7331, and NGC 7678) were carried out with the 6-meter telescope (BTA) of Russian Special Astrophysical Observatory with the Spectral Camera attached to the focal reducer SCORPIO in the multislit mode with a dispersion of 2.1A/pixel and a spectral resolution of 10A. 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 disks of spiral galaxies NGC 628, NGC 783, NGC 2336, NGC 7331, and NGC 7678 have been determined. The abundances in the NGC 783, NGC 2336, NGC 6217, and NGC 7678 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.