# Small-scale chemical abundance analysis in a blue compact dwarf galaxy   SBS 1415+437

**Authors:** Nimisha Kumari, Bethan L. James, Mike J. Irwin, Alessandra Aloisi

arXiv: 1901.08600 · 2019-02-13

## TL;DR

This study uses integral field spectroscopy to map chemical abundances in a blue compact dwarf galaxy, revealing uniformity in elemental ratios and providing insights relevant for high-redshift galaxy observations.

## Contribution

First detailed spatially resolved chemical abundance analysis in SBS 1415+437 using the direct T_e-method with high spatial resolution.

## Key findings

- No significant chemical variation across the region.
- Integrated spectra abundances agree with spatially mapped values.
- Results aid comparison with high-redshift galaxy data.

## Abstract

We use integral field spectroscopic (IFS) observations from Gemini Multi-Object Spectrograph-North (GMOS-N) to analyse the ionised gas in the principal star-forming region in the blue compact dwarf galaxy SBS 1415+437. The IFS data enable us to map the weak auroral line [O III] $\lambda$4363 at a spatial scale of $\sim$6.5 pc across a region of $\sim$143 $\times$ 143 pc$^2$. This in turn allows us to use the robust direct T$_e$-method to map the ionic and elemental abundances of nitrogen (N) along with the alpha-elements, oxygen (O), neon (Ne), sulphur (S) and argon (Ar). We utilise these abundances to map the relative abundances of N, Ne, S and Ar with respect to O. We segment this predominantly photoionised region of study into elliptical annuli on the basis of the H$\alpha$ flux distribution to study the variation of chemical abundances and their ratios, and find no significant chemical variation. We also perform chemical abundance analysis on the integrated spectra of the region under study and elliptical annuli within it. We find that the inferred abundances are in agreement with the median of the abundances obtained from the chemical abundance maps of the principal star-forming region and the mapped values within annuli.The finding has important implications for direct comparison with high-redshift observations, where spatial resolution is not available, and for a consistent approach to track chemical evolution across cosmic time.

## Full text

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## Figures

71 figures with captions in the complete paper: https://tomesphere.com/paper/1901.08600/full.md

## References

60 references — full list in the complete paper: https://tomesphere.com/paper/1901.08600/full.md

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Source: https://tomesphere.com/paper/1901.08600