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J0811+4730: the most metal-poor star-forming dwarf galaxy known
- Source :
- MNRAS 473, 1956 (2018)
- Publication Year :
- 2017
-
Abstract
- We report the discovery of the most metal-poor dwarf star-forming galaxy (SFG) known to date, J0811+4730. This galaxy, at a redshift z=0.04444, has a Sloan Digital Sky Survey (SDSS) g-band absolute magnitude M_g = -15.41 mag. It was selected by inspecting the spectroscopic data base in the Data Release 13 (DR13) of the SDSS. LBT/MODS spectroscopic observations reveal its oxygen abundance to be 12 + log O/H = 6.98 +/- 0.02, the lowest ever observed for a SFG. J0811+4730 strongly deviates from the main-sequence defined by SFGs in the emission-line diagnostic diagrams and the metallicity - luminosity diagram. These differences are caused mainly by the extremely low oxygen abundance in J0811$+$4730, which is ~10 times lower than that in main-sequence SFGs with similar luminosities. By fitting the spectral energy distributions of the SDSS and LBT spectra, we derive a stellar mass of M* = 10^6.24 - 10^6.29 Msun (statistical uncertainties only), and we find that a considerable fraction of the galaxy stellar mass was formed during the most recent burst of star formation.<br />Comment: 12 pages, 5 figures, accepted for publication in MNRAS
- Subjects :
- Astrophysics - Astrophysics of Galaxies
Subjects
Details
- Database :
- arXiv
- Journal :
- MNRAS 473, 1956 (2018)
- Publication Type :
- Report
- Accession number :
- edsarx.1709.00202
- Document Type :
- Working Paper
- Full Text :
- https://doi.org/10.1093/mnras/stx2478