ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691

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  • Additional Information
    • Publication Date:
      2016
    • Collection:
      Astrophysics
    • Abstract:
      We present spectroscopic observations of the nearby dwarf galaxy AGC 198691. This object is part of the Survey of HI in Extremely Low-Mass Dwarfs (SHIELD) project, which is a multi-wavelength study of galaxies with HI masses in the range of 10$^{6}$-10$^{7.2}$~M$_{\odot}$ discovered by the ALFALFA survey. We have obtained spectra of the lone HII region in AGC 198691 with the new high-throughput KPNO Ohio State Multi-Object Spectrograph (KOSMOS) on the Mayall 4-m as well as with the Blue Channel spectrograph on the MMT 6.5-m telescope. These observations enable the measurement of the temperature-sensitive [OIII]$\lambda$4363 line and hence the determination of a "direct" oxygen abundance for AGC 198691. We find this system to be an extremely metal-deficient (XMD) system with an oxygen abundance of 12+log(O/H) = 7.02 $\pm$ 0.03, making AGC 198691 the lowest-abundance star-forming galaxy known in the local universe. Two of the five lowest-abundance galaxies known have been discovered by the ALFALFA blind HI survey; this high yield of XMD galaxies represents a paradigm shift in the search for extremely metal-poor galaxies.
      Comment: 14 pages, 7 figures, 4 tables, accepted for publication in ApJ
    • Accession Number:
      10.3847/0004-637X/822/2/108
    • Accession Number:
      edsarx.1603.03798
  • Citations
    • ABNT:
      HIRSCHAUER, A. S. et al. ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691. [s. l.], 2016. DOI 10.3847/0004-637X/822/2/108. Disponível em: http://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=edsarx&AN=edsarx.1603.03798&custid=s6224580. Acesso em: 24 jan. 2020.
    • AMA:
      Hirschauer AS, Salzer JJ, Skillman ED, et al. ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691. 2016. doi:10.3847/0004-637X/822/2/108.
    • APA:
      Hirschauer, A. S., Salzer, J. J., Skillman, E. D., Berg, D., McQuinn, K. B. W., Cannon, J. M., … Aver, E. (2016). ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691. https://doi.org/10.3847/0004-637X/822/2/108
    • Chicago/Turabian: Author-Date:
      Hirschauer, Alec S., John J. Salzer, Evan D. Skillman, Danielle Berg, Kristen B. W. McQuinn, John M. Cannon, Alex J. R. Gordon, et al. 2016. “ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691.” doi:10.3847/0004-637X/822/2/108.
    • Harvard:
      Hirschauer, A. S. et al. (2016) ‘ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691’. doi: 10.3847/0004-637X/822/2/108.
    • Harvard: Australian:
      Hirschauer, AS, Salzer, JJ, Skillman, ED, Berg, D, McQuinn, KBW, Cannon, JM, Gordon, AJR, Haynes, MP, Giovanelli, R, Adams, EAK, Janowiecki, S, Rhode, KL, Pogge, RW, Croxall, KV & Aver, E 2016, ‘ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691’, viewed 24 January 2020, .
    • MLA:
      Hirschauer, Alec S., et al. ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691. 2016. EBSCOhost, doi:10.3847/0004-637X/822/2/108.
    • Chicago/Turabian: Humanities:
      Hirschauer, Alec S., John J. Salzer, Evan D. Skillman, Danielle Berg, Kristen B. W. McQuinn, John M. Cannon, Alex J. R. Gordon, et al. “ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691,” 2016. doi:10.3847/0004-637X/822/2/108.
    • Vancouver/ICMJE:
      Hirschauer AS, Salzer JJ, Skillman ED, Berg D, McQuinn KBW, Cannon JM, et al. ALFALFA Discovery of the Most Metal-Poor Gas-Rich Galaxy Known: AGC 198691. 2016 [cited 2020 Jan 24]; Available from: http://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=edsarx&AN=edsarx.1603.03798&custid=s6224580