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 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 [O III] 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 colour-magnitude diagram, inviting speculation that star formation in the galaxy only began in the last few Gyr.
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- February 2023
- galaxies: dwarf - galaxies: individual: HIPASS J1131-31 - galaxies: irregular - galaxies: star formation;
- Astrophysics - Astrophysics of Galaxies
- 11 pages, 7 figures, published in MNRAS