The Little Cub: Discovery of an Extremely Metal-Poor Star-Forming Galaxy in the Local Universe
| Autor: | Hsyu, Tiffany, Cooke, Ryan J., Prochaska, J. Xavier, Bolte, Michael |
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| Rok vydání: | 2017 |
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| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/2041-8213/aa821f |
| Popis: | We report the discovery of the Little Cub, an extremely metal-poor star-forming galaxy in the local Universe, found in the constellation Ursa Major (a.k.a. the Great Bear). We first identified the Little Cub as a candidate metal-poor galaxy based on its Sloan Digital Sky Survey photometric colors, combined with spectroscopy using the Kast spectrograph on the Shane 3-m telescope at Lick Observatory. In this letter, we present high-quality spectroscopic data taken with the Low Resolution Imaging Spectrometer at Keck Observatory, which confirm the extremely metal-poor nature of this galaxy. Based on the weak [O III] 4363 Angstrom emission line, we estimate a direct oxygen abundance of 12 + log(O/H) = 7.13 +/- 0.08, making the Little Cub one of the lowest metallicity star-forming galaxies currently known in the local Universe. The Little Cub appears to be a companion of the spiral galaxy NGC 3359 and shows evidence of gas stripping. We may therefore be witnessing the quenching of a near-pristine galaxy as it makes its first passage about a Milky Way-like galaxy. Comment: 8 pages, 3 figures, Accepted for publication in the Astrophysical Journal Letters |
| Databáze: | arXiv |
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