Exploring chemical homogeneity in dwarf galaxies: a VLT-MUSE study of JKB 18
| Autor: | Sergey E. Koposov, Andrew Emerick, Vasily Belokurov, Kristen B. W. McQuinn, Nimisha Kumari, Roberto Maiolino, Daniel P. Stark, B. James |
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| Přispěvatelé: | Belokurov, Vasily [0000-0002-0038-9584], Maiolino, Roberto [0000-0002-4985-3819], Apollo - University of Cambridge Repository |
| Rok vydání: | 2020 |
| Předmět: |
astro-ph.GA
Metallicity FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics 01 natural sciences 0103 physical sciences Galaxy formation and evolution Astrophysics::Solar and Stellar Astrophysics Spectroscopy 010303 astronomy & astrophysics galaxies: irregular Astrophysics::Galaxy Astrophysics Dwarf galaxy Physics 010308 nuclear & particles physics Star formation Astronomy and Astrophysics galaxies: dwarf Astrophysics - Astrophysics of Galaxies Galaxy Stars Supernova Space and Planetary Science Astrophysics of Galaxies (astro-ph.GA) galaxies: star formation galaxies: abundances Astrophysics::Earth and Planetary Astrophysics galaxies: evolution |
| Zdroj: | James, B L, Kumari, N, Emerick, A, Koposov, S E, McQuinn, K B W, Stark, D P, Belokurov, V & Maiolino, R 2020, ' Exploring Chemical Homogeneity in Dwarf Galaxies : A VLT-MUSE study of JKB 18 ', Monthly Notices of the Royal Astronomical Society, vol. 495, no. 3, pp. 2564-2581 . https://doi.org/10.1093/mnras/staa1280, https://doi.org/10.1093/mnras/staa1280 |
| DOI: | 10.17863/cam.54252 |
| Popis: | Deciphering the distribution of metals throughout galaxies is fundamental in our understanding of galaxy evolution. Nearby, low-metallicity, star-forming dwarf galaxies in particular can offer detailed insight into the metal-dependent processes that may have occurred within galaxies in the early Universe. Here we present VLT/MUSE observations of one such system, JKB 18, a blue diffuse dwarf galaxy with a metallicity of only 12+log(O/H)=7.6$\pm$0.2 (~0.08 Zsol). Using high spatial-resolution integral field spectroscopy of the entire system, we calculate chemical abundances for individual HII regions using the direct method and derive oxygen abundance maps using strong-line metallicity diagnostics. With large-scale dispersions in O/H, N/H and N/O of ~0.5-0.6 dex and regions harbouring chemical abundances outside this 1$\sigma$ distribution, we deem JKB 18 to be chemically inhomogeneous. We explore this finding in the context of other chemically inhomogeneous dwarf galaxies and conclude that neither the accretion of metal-poor gas, short mixing timescales, or self-enrichment from Wolf-Rayet stars are accountable. Using a galaxy-scale, multi-phase, hydrodynamical simulation of a low-mass dwarf galaxy, we find that chemical inhomogeneities of this level may be attributable to the removal of gas via supernovae and the specific timing of the observations with respect to star-formation activity. This study not only draws attention to the fact that dwarf galaxies can be chemically inhomogeneous, but also that the methods used in the assessment of this characteristic can be subject to bias. Comment: 18 pages, 14 figures, accepted for publication in MNRAS |
| Databáze: | OpenAIRE |
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