Oxygen and nitrogen abundances in nearby galaxies. Correlations between oxygen abundance and macroscopic properties

TL;DR

This study compiles and homogenizes spectra of HII regions in spiral galaxies to analyze oxygen and nitrogen abundances, revealing new correlations with galaxy properties and differences from previous calibration methods.

Contribution

It provides a homogeneous recalculation of abundances using the P-method and compares the resulting luminosity-metallicity relation with prior calibrations, highlighting differences and galaxy evolution insights.

Findings

The L-Z relation derived differs significantly from R_23-based calibrations.

Effective oxygen yields increase with luminosity and then plateau.

Irregular galaxies retain at least one-third of their produced oxygen.

Abstract

We performed a compilation of more than 1000 published spectra of HII regions in spiral galaxies. The oxygen and nitrogen abundances in each HII region were recomputed in a homogeneous way, using the P-method. The radial distributions of oxygen and nitrogen abundances were derived. The correlations between oxygen abundance and macroscopic properties are examined. There is a significant difference between the L-Z relationship obtained here and that based on the oxygen abundances determined through the R_23-calibrations. The oxygen abundance of NGC 5457 recently determined using direct measurements of Te (Kennicutt, Bresolin & Garnett 2003) agrees with the L-Z relationship derived here, but is in conflict with the L-Z relationship derived with the R_23-based oxygen abundances. The obtained L-Z relation for spirals is compared to that for irregulars. Our sample of galaxies shows evidence that the slope of the O/H-M_B relationship for spirals is slightly more shallow than that for irregulars. The effective oxygen yields were estimated for spiral and irregular galaxies. The effective oxygen yield increases with increasing luminosity from M_B=-11 to M_B=-18 (or with increasing rotation velocity from Vrot=10 km/s to Vrot=100 km/s) and then remains approximately constant. Irregular galaxies from our sample have effective oxygen yields lowered by a factor of 3 at maximum, i.e. irregular galaxies usually keep at least 1/3 of the oxygen they manufactured during their evolution.