Chemical Abundances Of LINER Galaxies — Nitrogen Abundance Estimations

By Keith Cowing
Status Report
April 26, 2024
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Chemical Abundances Of LINER Galaxies — Nitrogen Abundance Estimations
log(N/O) vs. 12+log(O/H) diagram. The color bars indicate the 𝜎frac value (left panel) and the H𝛼 fluxes in units of 10−17 erg/s/cm2 /spaxel (right panel) for each object in our sample — astro-ph.GA

In this work, we investigated the nitrogen and oxygen abundances in a sample of galaxies with Low Ionization Nuclear Emission Regions (LINERs) in their nucleus.

Optical spectroscopic data (3 600 – 10 000 Å) of 40 LINERs from the Mapping Nearby Galaxies (MaNGA) survey were considered. Only objects classified as retired galaxies, i.e. whose main ionization sources are post-Asymptotic Giant Branch (pAGB) stars, were selected. The abundance estimates were obtained through detailed photoionization models built with the cloudy code to reproduce a set of observational emission line intensities ratios of the sample.

Our results show that LINERs have oxygen and nitrogen abundances in the ranges of 8.0≤12+log(O/H)≤9.0 (mean value 8.74±0.27) and 7.6≤12+log(N/H)≤8.5 (mean value 8.05±0.25), respectively. About 70% of the sample have oversolar O/H and N/H abundances. Our abundance estimates are in consonance with those for Seyfert 2 nuclei and H ii regions with the highest metallicity, indicating that these distinct object classes show similar enrichment of the interstellar medium (ISM). The LINERs in our sample are located in the higher N/O region of the N/O versus O/H diagram, showing an expected negative correlation between these two parameters.

These results suggest that these LINERs mainly exhibit a secondary nitrogen production and could be acting some other mechanisms that deviate them from the usual theoretical secondary nitrogen production curve and the H ii regions observations. However, we did not find any evidence in our data able to support the literature suggested mechanisms. On the other hand, our results show that LINERs do not present any correlation between the N/O abundances and the stellar masses of the hosting galaxies.

C. B. Oliveira Jr., A.C. Krabbe, O. L. Dors Jr., I. A. Zinchenko, J. A. Hernandez-Jimenez, M. V. Cardaci, G. F. Hägele, G. S. Ilha

Comments: Accepted for publication in MNRAS
Subjects: Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2404.16631 [astro-ph.GA] (or arXiv:2404.16631v1 [astro-ph.GA] for this version)
Submission history
From: Celso B. Oliveira Junior
[v1] Thu, 25 Apr 2024 14:17:41 UTC (1,052 KB)

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