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J. L. Melbourne, J. J. Salzer (Wesleyan U.)
We present preliminary metal abundance results for a large sample of emission line galaxies (ELGs). Among our goals is the discovery of new low metallicity dwarf galaxies. Our sample is drawn from the KPNO International Spectroscopic Survey (KISS) which has discovered over 2000 ELG candidates to date. Follow up optical spectra have been obtained for ~700 of these objects. Three methods are used to analyze the spectra and obtain metal abundances. First we undertake a full elemental abundance determination for six galaxies for which high quality spectra exist. These spectra cover the full optical region from [OII]\lambda3727 to beyond [SII]\lambda\lambda6717,31 and include detection of [OIII]\lambda4363. We calculate electron temperatures, electron densities and elemental abundances using a full nebular analysis. We find two galaxies with Z~q 1/25 \cdot Z\odot. Using spectra of similar wavelength coverage but lacking [OIII]\lambda4363, we calculate secondary metallicity indicators (R23, p2, p3 and P). These determinations are possible for ~80 additional spectra. The results are used to calibrate metallicity-diagnostic diagrams, which allow us to estimate coarse metallicities for the several hundred remaining spectra. This large, homogeneously observed sample of star-forming galaxies is used to identify low metallicity candidates for future study and investigate the metallicity-luminosity relation.
The author(s) of this abstract have provided an email address for comments about the abstract: jmel@astro.wesleyan.edu