[Paper Review] Oxygen and nitrogen abundances in nearby galaxies. Correlations between oxygen abundance and macroscopic properties

L. S. Pilyugin, J. M. Vı́lchez+1 more|ArXiv.org|Jul 1, 2004

Galaxies: Formation, Evolution, PhenomenaPhysics and Astronomy179 references191 citations

TL;DR

This study compiles over 1,000 H ii region spectra from 54 spiral galaxies, re-estimates oxygen and nitrogen abundances using the P-method for consistent temperature-sensitive line analysis, and finds that oxygen abundance correlates strongly with luminosity, rotation velocity, and morphological type—with rotation velocity showing the tightest correlation. The derived luminosity–metallicity relation differs significantly from those based on R₂₃ calibrations, and direct Te-based abundances in NGC 5457 align with this new relation but conflict with R₂₃-based ones.

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.

Motivation & Objective

• To compile and homogenize oxygen and nitrogen abundance measurements from over 1,000 H ii region spectra in spiral galaxies.
• To recompute abundances using the P-method for consistent, temperature-sensitive analysis, avoiding biases from R₂₃-based calibrations.
• To examine correlations between oxygen abundance and macroscopic galaxy properties such as luminosity, rotation velocity, and morphological type.
• To compare the luminosity–metallicity relationship in spiral galaxies with that in irregular galaxies and assess differences in effective oxygen yields.
• To resolve discrepancies between direct Te-based abundances (e.g., NGC 5457) and R₂₃-based abundance determinations in the literature.

Proposed method

• Collected and compiled 1,000+ published spectra of H ii regions in 54 spiral galaxies from the literature.
• Recomputed oxygen and nitrogen abundances using the P-method, which relies on temperature-sensitive [O iii] λ4363 line ratios for accurate metallicity determination.
• Derived radial abundance distributions for oxygen and nitrogen, including central abundance extrapolations and abundance gradients.
• Used the oxygen abundance at r = 0.4R₂₅ (isophotal radius) as the representative characteristic abundance for each galaxy.
• Constructed luminosity–metallicity and rotation velocity–metallicity relations using P-method abundances.
• Estimated effective oxygen yields (y_eff) by comparing observed abundances to closed-box model predictions, assessing mass loss efficiency.

Experimental results

Research questions

• RQ1 How do oxygen and nitrogen abundances in H ii regions of spiral galaxies correlate with macroscopic properties such as luminosity, rotation velocity, and morphological type?
• RQ2 How does the luminosity–metallicity relationship derived from P-method abundances compare to those derived using R₂₃-based calibrations?
• RQ3 Does the direct Te-based oxygen abundance in NGC 5457 agree with the luminosity–metallicity relation derived from P-method abundances or with R₂₃-based relations?
• RQ4 How do the effective oxygen yields in spiral galaxies compare to those in irregular galaxies, and how do they vary with luminosity or rotation velocity?
• RQ5 What is the significance of the slope difference in the O/H–M_B relation between spiral and irregular galaxies?

Key findings

• The oxygen abundance in spiral galaxies correlates most strongly with rotation velocity, which shows a slightly tighter correlation than with luminosity or morphological type.
• The luminosity–metallicity relationship derived from P-method abundances differs significantly from those based on R₂₃ calibrations, with the latter overestimating metallicity at high luminosities.
• The direct Te-based oxygen abundance in NGC 5457 (1.685 × scale length) agrees with the P-method-based luminosity–metallicity relation but conflicts with the R₂₃-based relation from Garnett (2002).
• The slope of the O/H–M_B relationship for spiral galaxies is shallower (–0.079 ± 0.018) than for irregular galaxies (–0.139 ± 0.011), indicating a weaker dependence of metallicity on luminosity in spirals.
• Effective oxygen yield increases from M_B ~ –11 to M_B ~ –18 (or V_rot from ~10 to ~100 km s⁻¹) and then levels off, suggesting efficient metal retention in more luminous systems.
• Irregular galaxies in the sample retain at least 1/3 of their manufactured oxygen, implying effective oxygen yields are lowered by at most a factor of 3, in contrast to Garnett (2002)’s estimate of up to 90–95% loss.