2006/09/11 by Lisa J. Kewley, Warren R. Brown, Margaret J. Geller +2 · 57 citations
Physics and Astronomy · #Absolute magnitude #Astronomy and Astrophysical Research #Dwarf galaxy #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Metallicity #Redshift #Sky #Star formation #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/509135
published in The Astronomical Journal 133(3), 882-888 (Institute of Physics) · 12 pages, 3 figures, 3 tables. To be published in the Astronomical Journal
arxiv created 2006/09/11 · openalex publication_date 2007/01/23 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/08
We discuss the serendipitous discovery of an extremely metal-poor galaxy, SDSS 0809+1729, classified as a star in the Sloan Digital Sky Survey (SDSS). The galaxy has a redshift z = 0.0441 and a B -band absolute magnitude M B = -17.1. With a metallicity of log(O/H) + 12 ∼ 7.44 or ∼1/20 solar, this galaxy is among the 10 most metal-poor emission-line galaxies known. SDSS 0809+1729 is a blue compact galaxy (BCG) with a stellar age of ∼4.5 Myr, a star formation rate of 0.18 M ⊙ yr -1 , and a large gas-phase electron density (∼367 cm -3 ). Similar values of these parameters are common among other extremely metal-poor galaxies, including I Zw 18. SDSS 0809+1729 is, however, unusual among BCGs because it lies in the same region of the luminosity-metallicity diagram as the two lowest metallicity long-duration gamma-ray burst (GRB) hosts. For a given B -band luminosity, both nearby GRB hosts and SDSS 0809+1729 have systematically lower metallicities than dwarf irregulars, the majority of BCGs, and normal star-forming galaxies. Because the star formation properties of SDSS 0809+1729 are similar to nearby long-duration GRB hosts, SDSS 0809+1729 may be a potential GRB host. Identification of larger samples of similar extremely metal-poor objects may provide important insights into the conditions required to produce long-duration GRBs.