Peekaboo: the extremely metal poor dwarf galaxy HIPASS J1131-31

The dwarf irregular galaxy HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The galaxy resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8+-0.7 Mpc. Spectral optic...

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Published inarXiv.org
Main Authors Karachentsev, I D, Makarova, L N, Koribalski, B S, Anand, G S, Tully, R B, Kniazev, A Y
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 07.12.2022
Subjects
Color-magnitude diagram
Dwarf galaxies
Hubble Space Telescope
Irregular galaxies
Physics - Astrophysics of Galaxies
Red giant stars
Red shift
Star formation
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Summary:The dwarf irregular galaxy HIPASS J1131-31 was discovered as a source of HI emission at low redshift in such close proximity of a bright star that we call it Peekaboo. The galaxy resolves into stars in images with Hubble Space Telescope, leading to a distance estimate of 6.8+-0.7 Mpc. Spectral optical observations with the Southern African Large Telescope reveal HIPASS J1131-31 to be one of the most extremely metal-poor galaxies known with the gas-phase oxygen abundance 12+log(O/H) = 6.99+-0.16 dex via the direct [OIII] 4363 line method and 6.87+-0.07 dex from the two strong line empirical methods. The red giant branch of the system is tenuous compared with the prominence of the features of young populations in the color-magnitude diagram, inviting speculation that star formation in the galaxy only began in the last few Gyr.
ISSN:2331-8422
DOI:10.48550/arxiv.2212.03478