NOAO >   Observing Info >   Approved Programs >   2016B-0109

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Program Information for 2016B-0109


PI: John J Salzer, Indiana U., slaz@astro.indiana.edu
Address: Astronomy Department, 727 E. Third Street, Swain West 319, Bloomington, IN 47405 USA

CoI: Alec Hirschauer, Indiana U.

Title: Spectroscopy of Ultra-Low Metallicity Star-Forming Galaxies

Abstract: We propose to acquire abundance-quality spectra of approximately two dozen dwarf star-forming galaxies discovered in the H$alpha$ Dots survey (e.g., Kellar et al. 2012). The low-redshift H$alpha$ Dots sample represents some of the lowest-luminosity and lowest-metallicity galaxies known in the local universe. There are two primary goals of this project. The first is to explore the slope of the faint end of the luminosity-metallicity (L-Z) relation. A preliminary analysis using coarse abundance estimates for the H$alpha$ Dots suggests that the L-Z relation changes slope at the lowest luminosities. We require higher precision metallicity estimates in order to verify this result. Such a slope change could signal a paradigm shift in our understanding of how chemical evolution proceeds in galaxies. The second goal is to continue the search for extremely metal deficient (XMD) galaxies, building upon our recent discovery of the most metal-poor galaxy known. Several of the H$alpha$ Dot targets are located in the portion of emission-line ratio parameter space occupied by known XMDs. The discovery of even a few additional XMDs could ultimately lead to a better understanding of the physical processes that govern the chemical evolution in these low- abundance systems.

Program Type: Standard/Extragalactic

Scheduled Nights:
Run 1 (2016B):  KP-4m/KOSMOS -- 4n on Dec 01 - Dec 04 2016


National Optical Astronomy Observatory, 950 North Cherry Avenue, P.O. Box 26732, Tucson, Arizona 85726, Phone: (520) 318-8000, Fax: (520) 318-8360



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